NO. 3 CASSIDULOID ECHINOIDS — KIER I4I 



posterior to center; adapical surface low, adoral flattened but slightly 

 depressed around peristome. 



Apical system. — Sutures visible on specimen studied in d'Orbigny 

 Collection, definitely tetrabasal, with four genital pores in genital 

 plates, genital 2 extending posteriorly, separating posterior genital 

 plates. 



Ambulacra. — Petals well developed, conspicuous, broad, equal, 

 closed, with broad, tapering interporiferous zones. Pores conjugate, 

 outer pore greatly elongated transversely. 



Periproct. — Small, inframarginal, transverse. 



Peristome. — Slightly anterior, pentagonal, width equal to height. 



Floscelle. — Bourrelets well developed, jutting prominently. Phyl- 

 lodes not visible on any specimens studied but according to d'Or- 

 bigny 's figure, single pored with two series of pores in each half- 

 ambulacrum. Buccal pores probably present. 



Occurrence. — Upper Cretaceous (Maestrichtian) of France and 

 Holland. 



Location of type specimen. — Unknown. 



DOMECHINUS Kier, new genus 

 Type species. — Faujasia chelonium Cooke. 



GENERIC DESCRIPTION 



Medium size, elongate, blunted anterior margin, pointed posterior, 

 adapical surface inflated, adoral flat ; apical system monobasal with 

 four genital pores ; petals conspicuous, broad, equal, closed, con- 

 jugate pores, ambulacral plates single pored beyond petals ; periproct 

 marginal or slightly inframarginal, small, transverse; peristome 

 slightly anterior, small, pentagonal ; bourrelets strongly developed, 

 toothlike; phyllodes single pored, two series of pores in each half- 

 ambulacrum, six to eight pores in each outer series, only one or two 

 pores in each inner ; buccal pores present. 



Comparison with other genera. — Domcchinus is quite similar to 

 Faujasia, Lefortia, and Eiirypctalum. Its monobasal apical system 

 distinguishes it from Lefortia and Eurypetalum. Furthermore, in 

 Lefortia the periproct is longitudinal, whereas in Domcchinus it is 

 transverse. Faujasia differs in its peculiar apical system with the 

 genital pores in the interambulacra. 



Cooke (1955, p. 98) referred Domcchinus chelonium to Pygiirus. 



