242 



ECHINODERMATA ECHINOIDEA 



SUB-BRANCH III 



depressed dorsally. Amb petaloid for a variable distance ; pores of the petals 

 differing in shape, conjugated, and continued beyond in simple series. Peri- 

 stome slightly in front, or sometimes central. Periproct transversely elliptical, 

 infra-marginal. Widespread in Tertiary and Recent. 



Conolampas, Neolampas, A. Ag. Recent. Plesiolampas, Duncan and Sladen. 

 Eocene. Palaeolampas, Bell. Upper Cretaceous and Tertiary. 



Family 3. Collyritidae. ' d'Orbigny. (Dysasterinac, Gray.) 



Apical system disconnected, either elongate or sub-compact. Ambulacra similar ; 



bivium widely separated from the trivium; 

 floscelle absent. Jura to Recent. 



Collyrites, Desm. (Fig. 390). Test 

 ovoid, tumid, more or less truncated 

 posteriorly. Amb disjunct, the an- 

 terior one sometimes in a slight 

 groove. Width of the Amb increas- 

 ing toward the ambitus ; pairs of pores 

 in low primary plates. Periproct 

 posterior, supra -marginal, placed in 

 a groove. Apical system elongate, 

 separated by numerous small plates 

 belonging to the postero-lateral lAmb. 

 Very abundant in the Middle and 

 Upper Jura and Cretaceous. 



Dysaster, Ag. Differs from Colly- 

 rites in details of the apical system, 

 the basals not being separated by the 

 antero- lateral radial plates. Upper 

 Jura and Lower Cretaceous. 



Hyboclypeus, Agassiz. Jura. In 

 c, borso- fraclypeus, Gauthier. Upper Cre- 

 taceous. Grasia, Mich. Jura. 



FIG. 390. 



Collyriteselliptica,Desm. Callovian; Mamers, Sarth 

 A, B, Test in profile and from above, 1/1- 

 central system, enlarged. 



Metaporhinus, Mich. Test very tall, slightly longer than broad, sub-cordi- 



Fio. 391. 



Hyboclypeus giVbendus, Ag. Middle Jura ; Soleure, Switzerland. A, B, Dorsal and ventral views. C, Profile. 

 D, Apical system, enlarged. 



form, projecting upwards anteriorly, grooved and oblique behind. Anterior 



