96 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



Occurrence. — Upper Cretaceous (Maestrichtian), Fresville, 

 (Manche), France; Kunraad, Belgium. 



Location of type specimen. — According to Cotteau (i860, Pal. 

 franc, Cretace, p. 458), the holotype is in the d'Orbigny Collection 

 at the Museum National d'Histoire Naturelle, Paris. 



Remarks. — Further work is necessary on this species. d'Orbigny's 

 figures of the holotype show a specimen differing in some characters 

 from Lambert's specimens. Lambert's (1909, pi. i, figs. 17, 18) 

 specimen from Fresville (figured on my pi. 29, figs. 5, 6) has a 

 slightly truncated posterior margin, whereas, according to d'Orbigny's 

 figure, the posterior margin in the holotype is prolonged. The speci- 

 men that Lambert (1911c, pi. 2, figs. 22-25) figured from Kunraad 

 is much more elongate than d'Orbigny's specimen, and has its greatest 

 width anterior to the center instead of posterior as in d'Orbigny's 

 specimen. Perhaps Lambert's specimens are not conspecific with 

 d'Orbigny's. A reexamination of d'Orbigny's specimen should make 

 possible a decision on this question. It is interesting to note that 

 Lambert's figured specimen of O. pyriformis (Leske) (figured in 

 my pi. 29, figs. 7-9) is much more similar in shape to d'Orbigny's 

 holotype of O. gracilis. It differs in having the outer pore of a pore 

 pair greatly elongated transversely, whereas it is almost round in 

 0. gracilis. It is possible that O. pyriformis (Leske) and O. gracilis 

 are conspecific, and the study of many specimens should clarify this 

 situation. 



d'Orbigny shows double pores in the ambulacral plates beyond the 

 petals. This is an error on the part of the artist, as these pores are 

 not paired. 



? Synonym of OOLOPYGUS 



Pseudonucleus Lambert, 1920c. Ann. Soc. Linn. Lyon, vol. 66, p. 17. Type 

 species by monotypy, Pseudonucleus malladai Lambert. 



DESCRIPTION OF TYPE SPECIES 



PSEUDONUCLEUS MALLADAI Lambert 



Plate 44, figures 6-8 ; text figures 79, 80 

 Pseudonucleus malladai Lambert, op. cit., p. 17. 



Material. — The holotype and one topotype were studied in the 

 Lambert Collection at the Sorbonne, Paris. Both specimens are very 

 small and poorly preserved, being fractured, weathered, and partially 

 coated with secondary calcite. 



