CLASS I 



ECHINOIDEA 



289 



Echinoneus Leske. Amh narrow, actinally uiiequally broad, owing to the 

 obliquity of the large, triangulär peristome. Miocene to Recerit. 

 Caratomus Ag. Cretaceous. Amhlypygus Ag. Tertiary. 

 Pyijaulus Ag. (Fig. 406). Test small, thick ; apical System slightly 



Fk;. 406, 



Pyriaulus desmoulinsi Ag. Urgonian 

 (Sclirattenkalk) ; Säntis, Switzerland. i/i. 



Fig. 407. 



Pyr ina inscia (Ag.). Neoconiian (Hils) ; Berklingen, 



Brunswick. Vi- 



Amh narrow, widest at the ambitus ; pore-pairs in simple 

 the pores of a pair sometimes differently shaped. Cre- 



eccentric in front, 

 series, conjugated 

 taceous. 



Pyrina Desm. (Fig. 407). Like the preceding, but pores non-conjugated, 

 and the pairs separated by costae. Cretaceous and Eocene. 



Subfamily B. Echinobrissinae Duncan. 



Test depressed, elongate, tumid. Ambulacra sub-petaloid. Apical System and 

 peristome eccentric ; floscelle ahsent or rudimentary. Interamhulacra entering the 

 peristomal margin witli a single plate. Periproct supra-marginal. 



Nudeolites Lam. (Echinobrissus Breyn.) (Fig. 408). Test ovate, rounded in 

 front, broadest and more or less truncated behind; or rectangular, with the 



Fig. 40d 



A, B, Nudeolites dunieularis (Llhwyd). Cornbrash ; Egg, Aargau. Vi- C, D, N. scutatus (Lam.). Upper 

 Oxfordian ; Trouville, Cahados. C, Ventral aspect of large individual. D, Apical systeni, enlarged (after 

 Cotteau). 



angles rounded ; or sub-circular ; concave actinally. Amb unequal, open at 

 the end of the sub-petaloid parts ; pore-pairs in simple series, more or less 

 unequal in shape and size, the outer ones elongate ; below the sub-petaloid 

 parts the pores are in small oblique pairs, conjugate or not. Periproct at 

 Upper end of a groove situated on the abactinal area of the test. Abundant 

 in Upper Jura and Cretaceous ; present also in Eocene and late Tertiary. 

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