201 



NOTES 



ON 



Foreign Jurassic species of the genus POLYCYPHUS, nearly allied to British 



FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EnGLISH OoLITES. 



PoLYCYPHUs STELLATUs, Agassiz. Catalogue raisonne, Annal. So. Nat., tome vi, 3"' serie, 



p. 361. 



It closely resembles P. Normannus, but has fewer tubercles in the inter-ambulacral 

 areas. The type specimen, sent me by M. Michelin, appears to be only a variety of that 

 species. 



Formation. — Great Oolite of Ranville, Calvados. 



Collections. — MM. Deslongchamps and Michelin : rare. My cabinet. 



PoLYCYPHUs coRALLiNus, Cotteau, Etudcs sur les Echinides, pi. 21, figs. 1 — 7. 



A large, fine species, hemispherical above, and flat below ; the narrow ambulacra, 

 with two very regular rows of marginal tubercles, and a third row in the middle ; the 

 inter-ambulacra large, with a naked median depression ; ten rows of tubercles at the 

 equator, diminishing to two above, the horizontal rows slightly inclined. The promi- 

 nence and regularity of the ambulacra! tubercles forms a distinctive character of this 

 beautiful species. 



Formation. — Jura moyen " (Calcaire a chailles) des environs de Druyes : cette espece 

 est fort rare." Cotteau. 



Collection. — M. Cotteau. 



