140 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



EURYPETALUM Kier, new genus 

 Type species. — Echinolampas faujasii Desmoulins. 



GENERIC DESCRIPTION 



Test medium size, elongate, blunted anterior margin, pointed pos- 

 terior, adapical surface moderately inflated, adoral surface flattened; 

 apical system tetrabasal, anterior, four genital pores in genital plates ; 

 petals broad, conspicuous, closed, equal, conjugate pores, outer pore 

 greatly elongated transversely, ambulacral plates beyond petals single 

 pored ; periproct inframarginal, small, transverse ; peristome anterior, 

 pentagonal, width approximately equal to height ; bourrelets well de- 

 veloped, rounded ; phyllodes broad, single pored, with two series of 

 pores in each half -ambulacrum. 



Comparison zvith other genera. — This genus is similar to faujasia 

 in its shape and petal arrangement, but is distinguished from that 

 genus by its apical system, which is tetrabasal, with the genital pores 

 in normal position in the genital plates, whereas in Faujasia the 

 apical system is probably monobasal, with its genital pores not in the 

 apical system, but in the interambulacra. If d'Orbigny's (1856, 

 pi. 923, fig. 2) figure of the phyllodes in Eurypetalmn faujasii is 

 correct, this genus can be further distinguished by the more numerous 

 pores in its phyllodes than in F. apicalis. Eurypetalum is somewhat 

 similar to Lcfortia, but differs in having a transverse, inframarginal 

 periproct as opposed to the marginal, longitudinal periproct in 

 Lcfortia. It dififers from Domcchinus in that this latter genus has a 

 monobasal apical system and a much higher test. 



Range and distribution. — Upper Cretaceous (Senonian) of France, 

 Belgium, and Holland. 



DESCRIPTION OF TYPE SPECIES 

 EURYPETALUM FAUJASII (Desmoulins) 



Plate 17, figures 7, 8 

 Echinolampas faujasii Desmoulins, 1837. Etudes sur les ech., p. 346. 



Material. — Two specimens (one topotypic) studied in the Museum 

 of Comparative Zoology at Harvard, and one in the d'Orbigny Col- 

 lection at the Museum National d'Histoire Naturelle, Paris. All the 

 specimens are internal casts. 



Shape. — Medium size, adults 35 to 40 mm, long, elongate, with 

 gently curved anterior margin, pointed posterior, greatest width 



