34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



Greater Oolite form C. sinuatus, and the smaller Inferior Oolite 

 form C. plotii. I do not have sufficient specimens available to make 

 a decision, and hope that an English paleontologist will reexamine 

 all the specimens in the British collections and collect additional ma- 

 terial in order to tie in this material stratigraphically. It is probable 

 that an interesting evolutionary trend would be discovered. 



Synonym of CLYPEUS 

 Auloclypeiis Pomel, 1883. Class, meth., p. 60. Type species, Nuclcolites michclini 

 Wright, by subsequent designation, Mortensen (1948, p. 130). 



Remarks. — I have not seen any specimens of the t3^pe species of 

 this genus, but from a study of Cotteau's (1872, Pal. franc, Jur., 

 pi. 57) figures, it appears to be a Clypeus. Mortensen (1948, p. 130) 

 provisionally referred it to Clypeus but because of its short posterior 

 oculars thought it might be referred to Echmohrissus {=Nucleo- 

 lites). However, not all the species of Clypeus have long posterior 

 oculars; for example, in some specimens of Clypeus agassisi these 

 oculars are short. Furthermore, the test in C. michelini is much 

 larger, broader, and lower than in Nitcleolites. 



Synonym of CLYPEUS 

 Crotoclypeus Pomel, 1883. Class, meth., p. 60. Type species by subsequent 

 designation, Lambert and Thiery, 192 1, p. 344, Nucleolites agassizii Wright. 



DESCRIPTION OF TYPE SPECIES 



CLYPEUS AGASSIZI (Wright) 



Plate 5, figure 5, plate 8, figure i ; text figures 11-13 

 Nucleolites agassisi Wright, 1851. Ann. Mag. Nat. Hist., ser. 2, vol. 9, p. 368, 

 pi. 3, figs. 3a-c. 



Material. — Two specimens studied, one in the Museum of Com- 

 parative Zoology, Harvard ; the other in the U. S. National Museum. 



Shape. — Extremely large, circular in outline, inflated adapical sur- 

 face, greatest height slightly anterior to center, flat adoral surface. 



Apical system. — Slightly posterior to center, tetrabasal, madre- 

 porite very large, other genital plates small ; oculars V and I in 

 contact, in some specimens prolonged. Catenal plates joining apical 

 system to periproct present or absent (text figs. 12, 13). 



Ambulacra. — Petals broad, long, extending to margin, petals II, 

 III, IV longer than V, I. Interporiferous zones slightly wider than 

 poriferous, petals open. Poriferous zones very wide owing to great 

 width of outer pore, narrowing at extremities of petals. Pores con- 

 jugate, outer very slitlike, inner slightly elongated. 



Periproct. — Supramarginal, midway between apical system and 



