Genre Cassidulus  Lamarck, 1801

Système des animaux sans vertèbres, p.349

Espèce type  Cassidulus caribearum Lamarck, 1801, p.349 (par monotypie)

Extension stratigraphique (bibliographique, non vérifiée) : Eocène supérieur - Actuel

CASSIDULE (Cassidulus)

     Corps irrégulier, elliptique, ovale ou subcordiforme, convexe ou renflé, garni de très petites épines.

    Cinq ambulacres bornés et en étoile.

     Bouche subcentrale ; anus au-dessus du bord.

     Corpus irregulare, ellipticum, ovatum aut subcordatum, convexum vel turgidum, spinis exiguis obsidum.

     Ambulacra quinque, stellata, circumscripta.

     Os inferum, subcentrale, Anus suprà marginem. 

OBSERVATIONS.

    Les cassidules seraient des clypéastres, si elles n'avaient l'unus évidemment au-dessus du bord, et par là véritablement dorsal. Ceux des spatangues qui ont l'anus élevé dans le bord, pourraient être considérés comme ayant l'anus au-dessus du bord. Cenpendant ce serait à tort ; car, dans ces spatangues, l'anus est situé dans le haut d'une facette maginale, mais n'est pas réellement au-dessus du bord.

     C'est avec les nucléolites que les cassidules ont le plus de rapports, et peut-être devrait-on les réunir en un seul genre. Elles n'en diffèrent effectivement que par les ambulacres, lesquels sont bornés dans les cassidules, tandis que dans les nucléolites ils ne le sont pas. Mais sur les individus fossiles, il n'est pas toujours aisé de déterminer ce caractère des ambulacres.

Genus CASSIDULUS Lamarck

Cassidulus Lamarck, 1801. Système des animaux sans vertèbres, p.348. Type species by monotypy, Cassidulus cariboearum Lamarck.

Synonym : Glossaster Lambert

generic description

     Small, low, elongate ; apical system monobasal, four genital pores ; petals slightly or well developed, straight, open or closing distally, poriferous zones of same petal usually unequal, ambulacral plates beyond petals single pored ; periproct supramarginal, longitudinal or transverse, with groove extending from opening to posterior margin ; peristome anterior, pentagonal, transverse ; bourrelets well developed ; phyllodes widened, single pored with slight crowding of pores, one or two or no occluded pores ; buccal pores present ; adorally, tubercles much larger, scrobicules often polygonal, with bosses eccentric anteriorly ; adorally, naked, often pitted area in terterambulacrum 5, ambulacrum III.

     Comparison with other genera. - Cassidulus is very similar to Rhynchopygus but differs in having a monobasal apical system as opposed to the tetrabasal system in Rhynchopygus. As Cassidulus occurs later, in the Tertiary, whereas Rhynchopygus is from the Upper Cretaceous, and since

Cassidulus has a more advanced apical system, there is little doubt that it is descended from Rhynchopygus. Cassidulus differs from Rhyncholampas in having a smaller, more elongate test, narrower, nonlanceolate petals, a usually less posterior periproct, and phyllodes with fewer pores. It differs from Hypsopygaster in having more developed petals and less pointed bourrelets.

     Remarks. - This genus includes most of the Tertiary species that Lambert and Thiery referred to their Procassidulus, except for Twitchell's Cassidulus depressus, which Cooke (1959, p.64) considers a synonym of Eurhodia patelliformis (Bouve), Desor's Cassidulus amygdala, which also appears to be a Eurhodia, and Kew's Cassidulus mexicanus, which is a Rhyncholampas. Many of the pre-Tertiary species that Lambert and Thiery refer to Procassidulus, including the type species, have a tetrabasal apical system and

should be referred to Rhynchopygus. All the Tertiary species that they refer to Rhynchopygus, except R. dyasteroides Duncan, have monobasal apical systems and should be referred to Cassidulus. Cooke (1959, pp.56-59) refers four species to Cassidulus (Cassidulus), but three of them, C. sabistonenis Kellum, C. gouldii (Bouve), and C. ericsoni Fischer, are very large, have well-developed phyllodes, and probably should be referred to Rhyncholampas. The fourth, C. trojanus is small but has more developed phyllodes than are usually found in Cassidulus. This species, like several others, has characters of both Cassidulus and Rhyncholampas and cannot be referred devinitely to either. These intermediate forms blur the distinction between the two genera.

     There are three American west coast species that belong to Cassidulus : C. ellipticus Kew, C. californicus Anderson, and C. ynezensis Kew. I have tudied all the type specimens of theses species, which are in the Museum of Paleontology at Berkeley, Calif. The two cotypes of Cassidulus ellipticus Kew are both poorly preserved, but the specimen figured in Kew's (1920) plate 39, figure 3a, c, d, shows the adapical surface and is herein designated the lectotype. The phyllodes are not visible on either of these specimens, but from the small size of the low and very elongated test, supramarginal, transverse periproct, and monobasal apical system this species should be referred to Cassidulus. The neotype of Cassidulus californicus Anderson also should be referred to Cassidulus. Althrough the specimen is poorly preserved, enough of one ot the phyllodes is visible to see that it is very simple, with only one pore occluded in each haf-ambulacrum. The test is small and elongate, and the apical system is monobasal. The specimen figured by Grant and Hertlein (1938, pl.4, fig.7 ; pl.30, fig.7) is wrongly referred by them to C. californicus. It differs from the latter in having a much larger, more inflated test, strongly lanceolate petals with more unequal poriferous zones in each petal, more anterior apical system, more marginal periproct lacking and adapical overhang, a less depressed peristome, and less developed bourrelets. Apparently it is a new pecies of Rhyncholampas.

     Kew's Cassidulus ynezensis is represented by one very poorly preserved specimen which is slightly crushed, with a large part of the adapical surface missing, and so badly weathered that no details are discernible of the phyllodes. Kew referred this species to Rhynchopygus, but since it has a monobasal apical system, it is a Cassidulus. Grant and Hertlein (1938, p.109) consider C. ynezensis as a synonym of C. californicus, but the two species are quite distinct. C. ynezensis is larger, lower, with sharper margin, smaller peristome, and narrower petals. Range and distribution.

     Range and distribution. - Eocene to Recent of worldwide distribution.

Cassidulus ovalis (Cotteau,1856)

N° 38. Cassidulus ovalis, Cotteau, 1856.

     Espèce oblongue, ovale, légèrement renflée en dessus, subconcave en dessous, arrondie en avant, tronquée obliquement en arrière. Sommet excentrique en avant. Tubercules petits, serrés, plus développés près des pores buccaux. Anus supramarginal. Bouche s'ouvrant dans une dépression de la face inférieure, rapprochée du bord antérieur et

correspondant au sommet. - Voisine par sa taille du C. lapis cancri, cette espèce s'en distingue par sa forme plus renflée, plus ovale, tronquée moins obliquement en arrière, par sa face inférieure plus déprimée au milieu.

     Boussan (Haute-Garonne). Coll. Leymerie

N° 132. - Cassidulus ovalis, Cotteau, 1856.

Pl. 142, fig. 4-8

     Espèce de petite taille, oblongue, ovale, légèrement renflée en dessus, subconcave en dessous, arrondie en avant. Aires ambulacraires sensiblement pétaloïdes. Zones porifères composées, à la face supérieure, de pores très inégaux, les internes ovales, subcirculaires, les externes obliques, allongés et unis aux premiers par un sillon. Un peu au-dessous de l'ambitus, les pétales ambulacraires s'interrompent brusquement ; les pores deviennent simples, beaucoup plus petits, sont disposés par paires obliques et disparaissent au milieu des tubercules ; ils se montrent de nouveau près du péristome et forment un floscelle très apparent. Tubercules crénelés, scrobiculés, très petits en dessus, augmentant de volume à la face inférieure qui présente, dans le sens du diamètre antéro-postérieur, une bande dépourvue de tubercules, marquée çà et là de petites dépressions irrégulières. Péristome un peu excentrique en avant, allongé, entouré de cinq bourrelets saillants, alternant avec les phyllodes porifères. Périprocte supramarginal, ovale, correspondant à une dépression assez sensible du test. Appareil apical subpentagonal, remarquable par la grandeur de la plaque madréporiforme ; plaques génitales, au nombre de quatre, largement perforées.

     Hauteur, 10 millimètres ; diamètre antéro-postérieur, 17 millimètres ; diamètre transversal, 15 millimètres.

     Rapports et différences. - Cette espèce se distingue nettement de ses congénères et notamment du C. lapis-cancri, par sa forme plus renflée, plus ovale et tronquée moins obliquement, par son périprocte allongé, par sa face inférieure plus déprimée.

     Localité. - Boussan (Haute-Garonne). Eocène moyen.

     Musée de Toulouse (Coll. Leymerie).

     Explication des figures. - Pl. 142, fig. 4, C. ovalis, vu de côté ; fig. 5, face supérieure ; fig. 6, face inférieure ; fig. 7, face postérieure ; fig. 8, aires ambulacraire antérieure grossie. Ces cinq figures sont copiées dans les Echinides des Pyrénées, pl. IV, fig. 1-5.

Planche 142 (extrait)

Cassidulus ovalis (Cotteau,1856) - Lutétien, Aspe, Alicante, Espagne, 36 mm

Cassidulus trojanus Cooke, 1942 - Eocène supérieur, Hernando Cty, Floride, 28mm

Genre Eurhodia  Haime in d'Archiac & Haime, 1853

Description des animaux fossiles du groupe numulitique de l'Inde, p.213

Espèce type  Pygorhynchus morrisi Haime in d'Archiac & Haime, 1853, p.214 (par monotypie)

Extension stratigraphique (bibliographique, non vérifiée) : Eocène

Syn.

• Ravenelia Mac Crady, 1859, p. 283 ; Espèce type Pygorhynchus rugosa Ravenel, 1848

Eurhodia amygdala (Desor, 1863)

Mus. Zurich.

Eurhodia amygdala (Desor, 1863) - Eocène, Alicante, Espagne, 25 mm

Eurhodia amygdala (Desor, 1863) - Eocène, Alicante, Espagne, 22 mm

Eurhodia rugosa (Ravenel,1848) ideali  Kier,1980

Eurhodia rugosa ideali, new subspecies

Figures 7, 9 ; Plate 7 : figures 7-9

     Material. - Description based on over 100 specimens from Ideal (locality 12). Dimensions from 48 specimens.

     Shape and Size. - Length 17.4 to 49.1 mm, x=31.60 mm, test elongate, width 69.26 to 80.26 (x=75.07) percent L (SD=5.76, CV=24.35, N=48), sides relatively straight and parallel in some specimens, in others sides widening posteriorly, posterior margin truncated ; height 32.92 to 44.83 (x=38.16) percent L (SC=2.34, CV=19.81, N=47). Trough extending downward from periproct ; test depressed adorally along midline.

     Apical System. - Anterior, distance from anterior margin 43.18 to 49.51 (x=46.08) percent L (SD=3.62, CV=24.79, N=45) ; monobasal, 4 genital pores, present on smallest specimen.

      Ambulacra. - Anterior petal extending almost to anterior margin ; length 30.46 to 59.30 (x=36.39) percent L (SD=4.19, CV=36.15, N=41) ; width 9.46 to 13.94 (x=12.18) percent L (SD=0.95, CV=24.94, N=44) ; length of petals II, IV 25.0 to 33.81 (x=29.95) percent L (SD=2.78, CV=29.13, N=40) ; width 9.46 to 13.94 (x=11.75) percent L (SD=0.92, CV=24.95, N=41) ; length of petals V, I 31.89 to 43.62 (x=37.82) percent L (SD=3.65, CV=30.51, N=41) ; width 9.12 to 13.46 (x=11.41) percent L (SD=0.94, CV=25.75, N=42). Petals closing distally, poriferous zones equal, interporiferous zones slightly wider than single poriferous zone. Specimen 17.4 mm long with 40 porepairs in petal III, 40 in petal IV, 50 in petal V ; specimen 48.9 mm long with 98 porepairs in petal III, 90 in IV, 110 in V.

     Peristome. - Anterior of center, distance from anterior margin 34.25 to 38.46 (x=36.43) percent L (SD=2.95, CV=25.61, N=48) ; elongated longitudinally, height 9.36 to 16.54 (x=12.53) percent L (SD=0.7, CV=18.43, N=47) ; width 7.14 to 14.02 (x=10.58) percent L (SD=0.71, CV=21.96, N=47). Bourrelets strongly developed. Phyllodes (Figure 9A) single pored, approximately 26 pores in each phyllode, 6 in inner series in occluded plates in specimen 23mm long ; 28 in each phyllode, 8-9 in inner series in specimen, 41.7 mm long.   

     Periproct. - Supramarginal, transverse with trough extending posteriorly. Enclosed by interambulacral plates 8-12.

     Adoral Surface. - Small, irregularly arranged pits (Plate 7 : figure 8) in midzone of interambulacrum V ; two-thirds of length of ambulacrum III extending from extremity of phyllode ; first and second plates of interambulacra 2, 3 and in plate 3 adjoining ambulacrum III ; a few pits in plates 1 and 2 in interambulacra 4, 1. Adoral plate arrangement in Figure 9B.

     Type-Specimens. - Holotype USNM 264046 ; figured specimen USNM 264589.

     Occurences. - Castle Hayne Limestone, North Carolina : localities 2, 5, 8, Rose Hill locality 11, Ideal Cement Company quarry localities 12, 26, 28 ("early and late zones").

     Remarks. - Specimens of this subspecies are distinguished from specimens of Eurhodia rugosa rugosa by their much smaller pits on the adoral surface (compare Plate 7 : figure 2 with Plate 7 : figure 8). In Eurhodia rogosa ideali the specimens are wider in the larger specimens, although having similar width to length ratios in the smaller specimens (Figure 7B). The width-to-length ratio decreases with increase in size in E. rugosa rugosa. Small specimens of E. rugosa ideali have lower tests than in E. rugosa rugosa but larger specimens have imilar heights (Figure 7A). Finally, specimens of E. rugosa ideali commonly have petal III shorter in the smaller specimens than E. rugosa rugosa (Figure 7C). In all other characters the subspecies are indistinguishable including width, height, and position of the peristome (Figure 7D), location of the apical system in large specimens (Figure 7E), width of all petals and length of all petals except petal III, number of porepairs in the petals, and numbers of pores in the phyllodes. E. rugosa ideali occurs in the Castle Hayne of North Carolina and E. rugosa rugosa occurs in the Santee Limestone of South Carolina.

Images d'après Kier 1980, fig in texte 9A-B et pl.7, fig.7-9 (holotype USNM 264046)

Eurhodia rugosa (Ravenel,1848) ideali  Kier,1980 - Eocène, Ocala limestone, Floride, 34 mm

Eurhodia rugosa (Ravenel,1848) ideali  Kier,1980 - Eocène, Castle Hayne formation, Pender County, Caroline du Nord, 38 mm

Eurhodia rugosa (Ravenel,1848) depressa Kier,1980

Eurhodia rugosa depressa, new subspecies

Figures 7A, 10, 21, 22 ; Plate 7 : figures 10-12

     Material. - 62 specimens from Maple Hill (East Coast Company) locality 10 but only eight show adapical surface. Specimens occur in living position as shown by the filling of only the lower portion of the test with sediment - the upper part is hollow. The specimens occur at the bottom of an indurated bryozoan "hash" with the upper surface of the echinoids firmly cemented to the rock making it very difficult to clean this surface.

    Shape and Size. - Length 47.6 to 65.0 mm, x=56.6 mm, test elongate, width 66.34 to 69.33 (x=67.59) percent L (SD=4.69, CV=12.27, N=8), greatest width posterior to center, posterior margin truncated ; height 25.38 to 28.32 (x=27.43) percent L (SD=1.67, CV=11.08, N=6). Trough extending downward from periproct ; test depressed adorally along midline.

     Apical System. - Anterior petal extending almost to anterior margin ; length 34.33 to 35.93 (x=35.33) percent L (SD=2.65, CV=13.59, N=6) ; width 9.08 to 9.90 (x=9.41) percent L (SD=0.66, CV=12.71, N=6) ; length of petals II, IV 25.92 to 30.08 (x=27.91) percent L (SD=2.55, CV=16.51, N=6) ; width 8.92 to 9.92 (x=9.45) percent L (SD=0.64, CV=12.34, N=6) ; length of petals V, I 36.33 to 39.40 (x=37.63) percent L (SD=2.94, CV=14.16, N=6) ; width 8.46 to 9.76 (x=9.36) percent L (SD=0.51, CV=9.69, N=5). Petals closing distally, poriferous zones equal, interporiferous zones slightly wider than single poriferous zone. Specimen 49.0 mm long with 102 porepairs in petal III, 84 in petal IV, 106 in petal V ; specimen 56.9 mm long with 124 porepairs in petal III, 102 in IV, 136 in V.

     Peristome. - Anterior of center, distance from anterior margin 34.49 to 36.13 (x=35.14) percent L (SD=2.49, CV=12.66, N=7) ; elongated longitudinally, height 10.77 to 12.65 (x=11.90) percent L (SD=0.54, CV=8.16, N=7) ; width 9.62 to 11.74 (x=9.50) percent L (SD=1.03, CV=16.87, N=7). Bourrelets strongly developed. Phyllodes (Figure 10A) single pored, approximately 26 pores in each phyllode, 7 in inner series in occluded plates in specimen 50.4 mm long ; same in specimen 63.7 mm long.

     Periproct. - Supramarginal, transverse with trough extending posteriorly. Enclosed by interambulacral plates 8-12.

     Adoral Surface. - Small, irregularly arranged pits (Plate 7 : figure 11) in midzone of interambulacrum V ; two-thirds of length of ambulacrum III extending from extremity of phyllode ; first and second plates of interambulacra 2, 3 and in plate 3 adjoining ambulacrum III ; a few pits in plates 1 and 2 in terambulacra 4, 1. Plate arrangement on Figure 10B.

     Type Specimens. -  Holotype ISNM 264047 ; figured specimens USNM 264590, 264591.

     Occurences. - Castle Hayne Limestone, North Carolina : Maple Hill (East Coast Construction Company quarry) localities 10, 34 ("middle zone").

     Remarks. - This subspecies differs from E. rugosa rugosa found in the Santee Limestone of South Carolina and E. rugosa ideali found elsewhere in the Castle Hayne Limestone of North Carolina in having a lower test (Figure 7A). The pits on the adoral side of its test are similar in size to those in E. rugosa ideali and smaller than those in E. rugosa rugosa. In all other characters, specimens of this subspecies are similar to the other subspecies, including the width of the test, length and width of the petals, position of the apical system, and position, height, and width of the peristome.

Images d'après Kier 1980, fig in texte 10A-B et pl.7, fig.10-12 (holotype USNM 264047)

Eurhodia rugosa (Ravenel,1848) depressa Kier,1980 - Eocène, Castle Hayne formation, Pender County, Caroline du Nord, 39 mm

Genre Rhyncholampas  Agassiz, 1869

Preliminary report echini, deep water Florida straits, p.270

Espèce type  Pygorhynchus pacificus Agassiz,1873, p.554 (désignation subséquente de Lambert in Lambert & Thierry (1918), p.369)

Extension stratigraphique (bibliographique, non vérifiée) : Maastrichtien - Actuel

Syn.

• Anisopetalus Clark in Arnold & Clark, 1927, p. 44 ; Espèce type Anisopetalus ellipticus Clark in Arnold & Clark, 1927, p. 44

• Plagiopygus Lambert, 1898, p. 162 ; Espèce type Nucleolites grigonensis Defrance, 1825

• Pleuropygus Lambert, 1913, p. 127 ; Espèce type Nucleolites grigonensis Defrance, 1825

• Galerolampas Cotteau, 1889, p.1 ; Espèce type Galerolampas sorigneti Cotteau, 1889

• Gisopygus Gauthier in Fourteau, 1899, p. 648 ; Espèce type Rhynchopygus navillei de Loriol, 1881.

Genus RHYNCHOLAMPAS A. Agassiz

Rhyncholampas A. Agassiz, 1869. Bull. Mus. Comp. Zool., vol.I, p.270. Type species by subsequent designation, Lambert (1918, p.41), Pygorhynchus pacificus A. Agassiz.

Synonyms : Anisopetalus Arnold and Clark ; Galerolampas Cotteau ; ? Gisopygus Gauthier ; Plagiopygus Lambert.

GENERIC DESCRIPTION

     Medium to large, elongate, oval or with greatest width posterior to center, moderately to highly inflated ; apical system anterior, monobasal ; petals lanceolate, equal, closing, with unequal poriferous zones ; ambulacra single pored beyond petals ; periproct slightly supramarginal, marginal or slightly inframarginal, transverse ; peristome anterior, pentagonal, wider than high ; bourrelets moderately developed ; phyllodes single pored, widened, usually with two series of pores in each half-ambulacrum, approximately four pores in each inner series ; in some species three series o pores in each half ambulacrum ; buccal pores poresent ; tubercles on adoral surface much larger than on adapical, scrobicules large, bosses eccentric anterior ; naked, often pitted area in interambulacrum 5, ambulacrum III.

     Comparison with other genera. - Rhyncholampas is distinguished from Cassidulus by its larger test, broader, lanceolate petals, generally more posterior periproct, and more developed phyllodes with more occluded pores. Although the type species of these two genera are very distinct from one another, there are species which have some of the characters of both and are difficult to place definitely in one of them.

     Remarks. - Mortensen (1948, p.202) incorrectly states that when A. Agasiz established this genus he made Cassidulus cariboearum the type species. Furthermore, Grant and Hertlein (1938, p.107) are mistaken in saying that C. cariboearum is the type species by monotypy. Agassiz referred two species to his genus, C. cariboearum and R. pacificus, but did not select a type species. Lambert and Thiery designated R. pacificus. Mortensen says that even if R. pacificus were considered as the type species of Rhyncholampas, the genus would still be a synonym of Cassidulus. He states that R. pacificus has more developed phyllodes and that the pores in it petals are more unequal, but suggests that these differences may be due to the different size of the specimens examined, and that if specimens of the same size were compared, the differences might be so small as to be unimportant

for a generic distinction. This argument would be pertinent if the species C. cariboearum were bsed on immature specimens, and R. pacificus on adults. Such is not the case. Many specimens of C. cariboearum are known, and none are larger han 31 mm. in length. There is no evidence that these small specimens are not adults. Fortunately, there are two small specimens of R. pacificus in the U.S. National Museum, one 21 mm. long and the other 35 m., and these immature specimens are generically distinct from C. cariboearum. A phyllode in the smallest specimen already has three occluded pores (text fig.154) in each half-ambulacrum, whereas no occluded pores occur in specimens of the same size or even larger of C. cariboearum. It is true that the pores in the petals of the small specimen of R. pacificus are more equal, with the outer pore less elongated (pl.28, fig.1) than the outer pore in an adult. However, the shape of the petals in R. pacificus is quite different from the petals in C. cariboearum. In R. pacificus the petals are lanceolate with more of a tendency to close distally. This difference is evident even on the smallest specimen.

     Range and distribution. - Paleocene to Recent, of worldwide distribution. There are many species from the Cenozoic of eastern United States which Cooke has referred to Plagiopygus (which he considers a subgenus of Cassidulus) or Cassidulus (Cassidulus), which probably should be referred to Rhyncholampas, including R. sabitonensis Kellum, R. gouldii (Bouve), R. ericsoni (Conrad), R. alabamensis (Twitchell), and R. georgiensis (Twitchell). Kew's west coast species Cassidulus (Rhynchopygus) mexicanus is very large, with well-developed broad lanceolate petals, and should be reffered to Rhyncholampas. Unfortunately, on the holotype, and evidently the only specimen known of this species, the adoral surface is destroyed and nothing is known of the phyllodes. A photograph of the adapical surface is included herein on plate 29, figure 4. This species is quite similar to R. evergladensis (Mansfield) from south-eastern United States, also from the Late Miocene of Florida. Its phyllodes are probably similar to the very well developed phyllodes in R. evergladensis.

Rhyncholampas carolinensis (Twitchell, 1915)

Cassidulus (Pygorhynchus) carolinensis Twitchell, n. sp.

Plate LXVII, figures 2a-g.

     Determinative characters. - Test thin walled, oval in marginal outline, posterior end truncated ; sides and anterior end rounded ; upper surface convex, depressed, slightly more elevated posteriorly than anteriorly and with a rather prominent low, rounded ridge above the periproct ; under surface flat, concave around the peristome ; apex central or slightly excentric posteriorly. Ambulacral areas narrow. A narrow granulated, median band back of the peristome. Apical system excentric anteriorly ; madreporite slightly tumid. Peristome excentric anteriorly, directly beneath apical system, pentagonal, with a floscelle. Periproct elliptical, transverse,  supramarginal beneath and overhanging expansion of the test, whose edge is even with the posterior margin.

     Dimensions. - Length 36 millimeters ; width 32 millimeters ; height 18 millimeters. This specimen is about a fourth larger than the average.

     Description. - This species occurs in large numbers at several localities in North Carolina, notably in association with Echinolampas appendiculatus. The test is thin walled, regularly oval in marginal outline, the posterior end vertically truncated. The upper surface is uniformly convex, depressed, sides and anterior en rounded, slightly more elevated posteriorly than anteriorly and in the form of a low rounded ridge above the periproct ; under surface flat, tumid near the pargin, concave around the peristome. The apex is central, or slightly excntric posteriorly.

     The ambulacral areas are narrow, dorsal portions petaloid ; the petals long, rather narrow, nearly closing, the posterior pair slightly longer than the others which are nearly equal in length. The poriferous zones are rather narrow, faintly depressed, outer pores oblong, inner ones round, pairs of pores conjugate.

     The surface of the test, including the interporiferous areas and the ridges between the pairs of pores, is closely set with small imperforate tubercles set in deep scrobicules. Between the tubercles are minute granules. The tubercles increase in size on the under surface except along a narrow band back of the peristome, which is somewhat smooth but dotted with numerous granulations.

     The apical system is excentric anteriorly. There are four genital pores, the anterior pair being nearer together than the posterior ; and five perforated radial plates. The madreporite is large, oval and faintly tumid, as are the adjacent portions of the interambulacral areas.

     The peristome is somewhat large, pentagonal, excentric anteriorly, directly beneath the apical system, surrounded by a floscelle of which the bourrelets are rather prominent, granulated, and together form a nearly circular ring around the peristome.

     The periproct is elliptical, transverse, supramarginal, at the top of the posterior truncation ; beneath a rounded, trnasverse, somewhat protruding expansion of the test, whose edge is just even with the truncated posterior margin.

     Related forms. - Cassidulus carolinensis is closely related to C. conradi and  resembles it in a number of features, notably in the details of the periproct ; but it is to be separated by its less excentric apical system, by its less transverse peristome with the subcircular ring of bourrelets, by being broader, more rounded and less rostrate posteriorly, and by having a more marked concavity around its peristome. C. carolinensis also resembles C. georgiensis but is to be distinguished by the concavity around its peristome, its less obtuse and less angular posterior margin, and its lower and less oblique posterior truncation. Among European forms C. carolinensis greatly resembles Pygorhynchus maveri De Loriol  from the Tertiary of Switzerland (more so than does C. conradi), but differs in having its periproct higher up on the posterior surface, and in the failure of the expansion of the test over the periproct to protrude noticeably beyond the posterior margin. In a number of features C. carolinensis is similar to Pygorhynchus grignonensis (Defrance) Agassiz from the Eocene of France, but it can be separated by its more depressed form and the higher relative position of its periproct.

     Localities. - Smith Creed (type), Rochy Point, and Wilmington, N. C.

     Geologic horizon. - Castle Hayne limestone, upper Eocene or Oligocene.

     Collections. - Johns Hopkins University (T 2004) ; U. S. National Museum.

Planche LXVII (extrait)

Rhyncholampas carolinensis (Twitchell, 1915) - Eocène, Castle Hayne formation, Caroline du Nord, 28 mm

Rhyncholampas grignonensis (Defrance, 1825)

RHYNCHOLAMPAS GRIGNONENSIS (DeFrance)

Plate 28, figures 4-8 ; text figures 151, 152

Nucleolites grignonensis DeFrance, 1825. Dict. sci. nat., vol.35, p.214

     Material. - Two specimens studied in the collecitons of the U.S. National Museum, and several, including Cotteau's figured specimen, in the Ecole Nationale Supérieure des Mines, Paris.

     Shape. - Medium size, oval, inflated, greatest width and height posterior to center ; margin gently rounded except for slight posterior truncation, peristome depressed.

     Apical system. - Anterior, monobasal, madreporite inflated.

     Ambulacra. - Petals narrow, petal III shorter than others, II and IV extending over two-thirds distance to margin ; petals V and I over one-half distance ; interporiferous zones over twice width poriferous zone ; petals closing distally ; poriferous zones depressed, of unequal length : one more pore pair in right zone of petal III, two more in posterior zones of petals II and IV, six more in outside zones of petals I and V ; this character variable with specimens ; pores conjugate, outer pore elongate transversely, inner smaller and round.

     Adoral interambulacra. - Single plate (text fig.152) at peristome, preceded by two alternating plates, one much larger than the other in interambulacrum 3, smaller plate adjacent to ambulacrum III ; in interambulacra 1 and 4 smaller plate adjacent to ambulacra I and V respectively ; in interambulacrum 5 adjacent to ambulacrum I ; plates preceding these regularly alternating, of approximately equal size.

     Periproct. - Marginal to slightly supramarginal ; transverse with slight groove at adoral side of opening.

     Peristome. - Anterior, depressed, pentagonal.

     Floscelle. - Bourrelets well developed (pl.28, fig.8) ; vertically sided. Phyllodes (text fig.151) windened single pored, two series in each half-ambulacrum ; seven or eight pores in each outer series, four to five in each inner series ; buccal pores, sphaeridia present.

     Tuberculation. - Adorally, tubercles larger ; naked median band in terambulacrum 5, short length at ambulacrum III.

     Occurence. - Middle Eocene of France.

     Location of type specimen. - According to Lambert and Jeannet (1928, p.126) the type is in the Ecole Nationale Supérieure des Mines.

Rhyncholampas grignonensis (Defrance, 1825) - Lutétien moyen, Aisne, France, 33 mm