244 



ECHINODERMATA ECHINOIDEA 



SUB-BRANCH III 



the elongate apical system, its pairs of pores numerous and small, the rows 

 wide apart. Paired Amb more or less curved, open distally, with dissimilar 



PIG. 



A, B, Holaster subglobosus, Ag. Cenomanian ; Rouen. 1/1- 

 enlarged. 



, H. suborliculuris, Defr. Dorso-central system, 



pores. Peristome much sunken, crescent -shaped, broad. Periproct supra- 

 marginal. Upper Cretaceous. H. radiatus, Lam. sp. 



Cardiaster, Forbes (Stegaster, Pomel, p.p.) Similar to Holaster, but anterior 

 groove deeper and with angular margin. Periproct oval, placed in a depression 

 in the truncated posterior face. A more or less complete marginal fascicle 

 passing below the periproct. Cretaceous. 



Sub-genus Jnfulaster, Hagw. Test high in front, narrow ; anterior groove deep and with 

 strong lateral keels. Fascicle absent. Upper Cretaceous. 



Hagenowia, Duncan (Cardiaster, Forbes, p.p. ; Stegaster, Pomel, p.p.) 

 Upper Cretaceous. 



Urechinus, Cystechinus, A. Ag. Late Tertiary and Eecent. Calymne, 

 Wyv. Thorns. Recent. Enichaster, de Loriol. Oligocene. All with uni- 

 porous Amb. 



Stenonia, Desor. Like Echinocorys (Ananchytes), except that the apical 

 system is compact, and the Amb equal. The solitary species, S. tuberculata, 

 Defr. sp., is abundant in the Upper Cretaceous (Scaglia) of the Southern Alps 

 and the Apennines. 



Family 2. Spatangidae. Wright. 



Test ovoid or cordiform, longer than broad, with numerous plates, and usually 

 with an anterior groove. Ambulacra in a bivium and trivium, the anterior differing 

 from the others in shape and construction. Pairs of pores of the petaloid parts 

 differing from the others. Fascioles present or absent. Cretaceous to Recent. 



SECTION A. ADETES. All fascioles absent. 



Isaster, Desor. Petals not closed. Peristome large, with a posterior 

 labrum. Cretaceous. 



Epiaster, d'Orb. (Macraster, Roemer.) Anterior Amb in a groove ; paired 



