NO. 3 CASSIDULOID ECHINOIDS — KIER 6l 



large usually extending posteriorly only to genital plates 4 and i, 

 but in some specimens (text fig. 31) extending more posteriorly, 

 separating these genitals; oculars V and I large, in some specimens 

 short (text fig. 30), in others long, extending posteriorly (text 

 fig. 32) ; catenal plates extending from posterior oculars to periproct 

 present (text fig. 32) in few specimens, but usually absent; no 

 complementary plates on any specimens studied by this author, but 

 Cotteau (1872, Pal. franc, Jur., pi. 'j'j, fig. 5) and Beurlen (1933, 

 p. 58) show one in their figures. 



Ambulacra. — Petals well developed, open, equal length, extending 

 two-thirds distance to margin, flush with test; interporiferous zones 

 almost twice width of poriferous zones; poriferous zones narrowing 

 distally, pores conjugate, outer pore transversely elongate, inner 

 circular, 



Periproct. — Supramarginal, between one-third and one-half dis- 

 tance from apical system to posterior margin ; longitudinal, slight 

 groove from apical system to periproct, deep groove from periproct 

 to posterior margin, groove continuing to adoral surface. 



Peristome. — Anterior, depressed, pentagonal, wider than high. 



Floscelle. — Bourrelets slightly developed ; phyllodes double pored, 

 arranged in two series in each half -ambulacrum, approximately 10 

 pore pairs in each outer series, 4 to 6 in each inner (text fig. 49). 



Tuherculation. — Tubercles perforate, crenulate, larger adorally 

 than adapically. 



Occurrence. — Upper Jurassic (Oxfordian-Rauracian) of England, 

 France, and Switzerland. 



Location of type specimen. — Unknown. 



Figs. 36-43. — 36, NucleoUtes burgundlae (Cotteau) : Apical system showing 

 few complementary plates on specimen in Museum of Comparative Zoology, 

 Harvard, from Jurassic (Bathonian) at Selongey (Cote-d'Or), France, X.12. 

 37, NucleoUies brodlei (Wright) : Apical system with large genital 2 separating 

 posterior oculars, from specimen in Museum National d'Histoire Naturelle, 

 Paris, Jurassic (Portlandian), St. Saire, France, X I5- 38, NucleoUtes gracilis 

 Agassiz : Phyllode of ambulacrum V of holotype in Museum of Comparative 

 Zoology, Harvard, from the Jurassic (Upper Oxfordian) at Raedersdorf Haute, 

 Switzerland, X 10. 39, NucleoUtes placentula (Desor) : Phyllode of specimen 

 from De Loriol Collection, Museum d'Histoire Naturelle, Geneve, Switzerland, 

 from the Lower Cretaceous (Aptian) at La Presta (Neuchatel), Switzerland, 

 X 15- 40, NucleoUtes lorioU (Cotteau) : Phyllode of specimen in Museum Na- 

 tional d'Histoire Naturelle, Paris, from the Middle Jurassic (Bajocian) at 

 St. Michiel, France, X I5- 41, NucleoUtes rotundus (Peron and Gauthier) : 

 Phyllode of ambulacrum I of specimen in Lambert Collection (No. 253), Sor- 

 bonne, Paris, from the Cretaceous (Cenomanian) at Bou Saada, Algeria, X lO- 

 42, NucleoUtes amplus Agassiz: Phyllode of ambulacrum H of specimen in 

 Naturhistorisches Museum (No. M1521/1), Basel, Switzerland, from Middle 

 Jurassic (Bathonian), Discoideen-Schichten, Aargauer, Jura, Herznach, Switzer- 

 land, X 15- 43, NucleoUtes orbicularis (Phillips) : Phyllode of ambulacrum IV 

 of specimen J18T45 in Sedgwick Museum, Cambridge, England, from Scar- 

 borougln, Yorkshire, England, X 10. 



