240 



ECHINODERMATA ECHINOIDEA 



SUB-BRANCH III 



upper end of a groove situated on the abactinal area of the test. Abundant in 

 Upper Jura and Cretaceous ; present also in Eocene and late Tertiary. 



FIG. 386. 



A. B, Echinobrissus clunicularis, Llhwyd sp. Cornbrash ; Egg, Aa 

 j>per Oxford! 

 (after Cottean). 



. 1 sp. Cornbrash ; Egg, Aargau. l/i C, D, E. scutatus, Lam. sp. 

 Upper Oxfordiau ; Trouville, Calvados. C, Ventral aspect of large individual. D, Apical system, enlarged 



Sub-genus Dochmostoma, Duncan (Trematopygus, d'Orb.) Like the preceding, but with 

 oblique peristome. Cretaceous. 



otriopygus, d'Orb. Cretaceous. Ilariona, Dames. Eocene. 



Family 2. Cassidulidae. Agassiz. 



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

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

 forming with the single, swollen, and ornamented interambulacral peristomial plates 

 a floscelle. Jura to Kecent. 



Cassidulus, Lam. (Fig. 387). Test small, oblong, depressed, convex 

 dorsally, flat actinally. Amb short, sub-petaloid, not closing ; pores continued 



from the middle part to the well- 

 developed floscelle. Peristome 

 eccentric in front ; periproct supra- 

 marginal, longitudinally elongated. 

 Cretaceous and Eocene. 



Sub - genus Rhynchopygus, d'Orb. 

 Periproct transversely elongate, with over- 

 hanging rostrum. Cretaceous to Recent. 



Sub -genus Pygorhynchus, Ag. Test 

 concave actinally, with long petals. Peri- 



FlG - 38 7- stome and periproct longest transversely. 



i lapis-cancri, Lam. A, Test in three positions. Cretaceous to Miocene. 

 -C, Floscelle, enlarged. 



Echinanthus, Breyn. Test thin, 



ovoid, low, convex dorsally, and concave actinally. Amb unequal, petaloid, 

 usually short. Peristome eccentric in front, with well-developed pentagonal 

 floscelle. Periproct oval, marginal or supra-marginal, at the top of a longi- 

 tudinal groove. Upper Cretaceous and Eocene. 



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

 Paralampas and Neocatopygus, Duncan and Sladen. Eocene. Catopygus, Ag. 



