290 



ECHINODERMATA—ECHINOZOA 



PHYLUM IV 



Subgenus Docfiviostoma Duncan {Trematopygus d'Orb.). Like the preceding, but with 

 oblique peristome. Cretaceous ; Europe and North America. 



Botriopygus d'Orb. Cretaceous. Ilariona Dames. Eocene. 



Family 2. 



Oassidulidae Agassiz. 



Test variable in shape. Ambulacra petaloid, sub-petaloid or apetalous dorsally, 

 and with crowded doubling of the pairs of pores close to the peristomal margin, 

 forming with the single, swollen and ornamented interambulacrcd peristomal plates a 

 floscelle. Jura to Recent. 



Cassidulus Lam. (Fig. 409). Test small, oblong, depressed, convex 



dorsally, flat actinall3^ Amb narrow, 

 sub-petaloid, not closing ; pores con- 

 tinued from the middle part to the 

 well-developed floscelle. Peristome 

 eccentric in front ; periproct supra- 

 marginal, longitudinally elongated. 

 Cretaceous and Eocene. 



Subgenus Rhynco2nj(]iis d'Orb. Periproct 

 transversely elongate, with overhanging 

 rostrum. Cretaceous to Recent. 



Subgenus Fygorhynchus Ag. Test con- 

 cave actinally, with long petals. Peris- 

 tome and periproct longest transversely. 

 Cretaceous to Miocene. 



Stigmatopygus d'Orb. Cretaceous. Eurhodia'd' Arch, and Haime. Eocene. 

 Paralampas and Neocatopygns Duncan and Sladen. Eocene. Catopygus Ag. 

 Cretaceous. Studeria Duncan. Tertiary and Recent. Phyllobrissus Cotteau. 

 Jura and Cretaceous. 



Clypeus Agassiz. Test large, low, nearly flat actinally. Ainb wide, 

 petaloid, not closing dorsally, narrow at the ambitus and actinally. Pore- 



Fifi. 409. 



Cassidulus lapis-cancri Lam. A, Test in three positions. 

 B, Floscelle, enlarged. 



I'l/gurus roi/cria/m.s Colteau. Kiiumcrid^'ian ; Tiinnjesberg, iii.'ai llanuvor. -J, B, Dursal aiid ventral views 

 of test, '^U natural size. L', Apical system, enlarged. D, Ambulacral plates, magnified. 



pairs in the petaloid parts with the inner pore small and circular, the outer 



