NO, 3 CASSIDULOID ECHINOIDS — KIER IO5 



subpentagonal ; bourrelets present ; phyllodes slightly broadened, sin- 

 gle pored, approximately six pores in each outer series in each half- 

 ambulacrum, two in each inner; buccal pores. 



Comparison with other genera. — Arnaudaster is very similar to 

 Parapygus and perhaps should be considered a synonym of it. It 

 differs only in having a more cylindrical shape, and more unequal 

 poriferous zones in the same petal. 



Remarks. — Only one species of this genus is known. Cooke (1955, 

 p. 96) attributed a Late Albian species {\\\s Arnaudaster colomhianus) 

 to this genus, but I do not believe that it is congeneric with A. 

 gauthicri. The most important difference between the two species 

 is that the phyllodes in Cooke's species are double pored (text fig. 89) 

 with many pore pairs, and with no buccal pores, whereas in A. 

 gauthieri they are single pored with few pores, and with buccal pores. 

 Furthermore, in Cooke's species the poriferous zones are approxi- 

 mately equal in length, but in A. gauthieri they are very unequal. On 

 his paratype (USNM 108696) the apical system is well preserved 

 and is definitely tetrabasal (text fig. 88). This species probably 

 should be referred to Pygorhynchus. 



Range and distribution. — Cretaceous (Cenomanian). France. 



DESCRIPTION OF TYPE SPECIES 



ARNAUDASTER GAUTHIERI Lambert 

 Plate 15, figures 5-7; text figure 87 



Arnaudasier gauthicri Lambert, 1920a. Mem. Soc. Acad. Aube, vol. 84, 

 pp. 152-153, pl- I, figs. 1-4- 



Material. — The holotype and only known specimen w-as studied in 

 the Lambert Collection. This specimen is well preserved although 

 the sutures in the apical system are not clear. 



Shape. — IMedium size, holotype 28 mm. long ; subcylindrical, with 

 rounded margins and straight sides. Greatest height posterior, adoral 

 surface flat. 



Apical system. — Anterior, four genital pores, madreporite large, 

 pierced with many pores, apparently tetrabasal from position of 

 genital plates, although sutures not clear. 



Ambulacra. — Petals well developed, broad, closing distally. Inter- 

 poriferous zones almost twice width of poriferous zone; pores con- 

 jugate, outer pore elongated obliquely, inner round or slightly elon- 

 gated. Poriferous zones unequal, posterior zones of petals II and 

 IV longer with 8 to 10 more pore pairs than anterior zones ; in petal 



