FOREIGN JURASSIC CLYPEI. 387 



Formation. — Great Oolite, near Mamers Sarthe. 

 Collection. — M. Michelin ; very rare. 



Clypeds Rathieri, Cotteau. Echinides Foss., de rYonne, pi. vi, p. 71. 



Test elongated, very flat on the dorsal surface, and concave at the base ; anterior 

 border rounded, and sub-truncated ; posterior half of the test much wider and 

 thicker ; posterior border rostrated. Ambulacral areas widely petaloid in the middle of 

 the dorsal surface, narrowly lanceolate near the disc, and contracted near the border; 

 anal valley short, narrow, and marginal; occupying the lower third of the inter-ambu- 

 lacrum, and forming a groove in the posterior border ; mouth-opening small, sub-central ; 

 peristome surrounded by five lobes. 



Dimensions. — Height, six tenths of an inch ; antero-posterior diameter, two inches 

 and a half; transverse diameter, two inches and a quarter. 



Formation. — Siliceous beds of the Forest marble (Great Oolite) at Chatel-Gerard, 

 Yonne. 



Collection. — M. Rathier ; very rare. 



Clypeus Osterwaldi, Besor. Synopsis des Echinides Foss. p. 277. 



Test large, depressed, enlarged, and rostrated posteriorly ; anal valley very narrow, 

 extending to the apical disc, which is central. Poriferous zones, in width about one half 

 the ambulacral area ; base, much undulated ; mouth-opening excentral ; peristome, with 

 five lobes and a penta-phylloid rosette, in which additional pores are arranged in double and 

 triple oblique ranks. 



Formation. — " Great Oolite (Bathonien) de Noiraigue (Canton de Neuchatel) au 

 dessous des marnes a Discoidees. Abondant." Desor. 



Collections. — M. Gresley, Mus. de Neuchatel. 



Clypeus rostratus, Bemr. Synopsis des Echinides Foss. p. 278. 



Test elevated, sub-conical ; posterior border much rostrated ; anal valley very much 



