NO. 3 CASSIDULOID ECHINOIDS — KIER 1 57 



jugate pores, outer pore slitlike ; petals V and I longer than others, 

 petal III very short, widely open; beyond petaloid portion single 

 pore in each ambulacral plate but with pores arranged in double 

 series (text fig. 131) almost to margin; ambulacral plates beyond 

 other petals single pored. 



Periproct. — Inframarginal, slightly longitudinal, opening very large. 



Peristome. — Very eccentric anteriorly, higher than wide, pentag- 

 onal. 



Floscelle. — Bour relets slightly developed ; phyllodes (text fig. 129) 

 slightly widened, single pored, pores in two series in each half-ambu- 

 lacrum, five to six pores in each series ; minute buccal pores (text 

 fig. 130). 



Tubercidatiofi. — Adorally, tubercles only slightly larger than 

 adapically, narrow naked granular zone in interambulacrum 5. 



Occurrence. — Cretaceous (Cenomanian) of Syria; collected by 

 Dubertret. 



Location of type specimen. — Holotype in Museum National d'His- 

 toire Naturelle, Paris. 



Synonym of GENTILIA 



Thomasaster Lambert, 1920b. Rev. crit. paleozool., vol. 24, p. 138 ; pro Thoniasia 

 Lambert, 1918; non Poche, 1900; nee. Ruebsaamen, 1910. Type species by 

 original designation, Archiacia araidahensis Gauthier. 



Remarks. — Both Lambert (1937, p. 78) and Mortensen (1948, 

 p. 325) suggested that Thomasaster probably was not distinct from 

 Gentilia. I have not seen any specimens of the type species, but from 

 Gauthier 's description, it appears to be congeneric with Gentilia. 



Family CASSIDULIDAE Agassiz and Desor, 1847 



Small to large, elongate, flat adoral surface; apical system anterior, 

 tetrabasal or monobasal ; periproct supramarginal to marginal, longi- 

 tudinal or transverse ; peristome anterior, oval or pentagonal, trans- 

 verse ; petals broad, usually equal length, often inconspicuous, porif- 

 erous zones of unequal length in most Tertiary species, ambulacral 

 plates beyond petals double pored in pre-Senonian species ; bourrelets 

 well developed ; phyllodes widened, double or single pored, one or 

 more series of pores in each half -ambulacrum ; buccal pores absent 

 in pre-Senonian species ; tubercles much larger adorally than adap- 

 ically, naked granular zone in interambulacrum 5. 



Genera. — Rhynchopygus, Nucleopygiis, Hypsopygaster, Ochetes, 

 Cassidulus, Rhyncholampas. 



