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. 

Fic. 386. 
A, B, Echinobrissus clunicularis, Linwyd sp. Cornbrash; Egg, Aargau. 1/,. C, D, E. scutatus, Lam. sp. 
Upper Oxfordian ; Trouville, Calvados. C, Ventral aspect of large individual. D, Apical system, enlarged 
(after Cottean). 
Sub-genus Dochmostoma, Duncan (Trematopygus, dOrb.) Like the preceding, but with 
oblique peristome. Cretaceous. 
Botriopygus, VOrb. Cretaceous. Jlariona, 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 Recent. 
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- 

Fic, 387. stome and periproct longest transversely. 
Cussidulus lapis-cancri, Lam. A, Test in three positions. Cretaceous to Miocene. 
B, Floscelle, enlarged. 
‘ Echinanthus, Breyn. Test thin, 
ovoid, low, convex dorsally, and concave actinally. dmb 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, @Orb. Cretaceous. Huwrhodia, d Arch. and Haime. Eocene. 
Paralampas and Neocatopygus, Duncan and Sladen. Eocene. Catopygus, Ag. 
