FOREIGN JURASSIC COLLYRITIDtE. 329 



Formation. — Corallien of Chatel-Censoir, (Yonne). 



Collection. — M. Cotteau, a single specimen ; a plaster mould in ray cabinet. 



Grasia elongata, MicJielin. Revue et Mag. de Zool., No. 8, 1854. 



Hybocltpus elongatus. Albin Gras, Cat. des Fossiles de I'lsere, tab. ii, fig. 1 — 3. 



A large urchin, very much elongated, measuring seven centimetres in length, by four 

 in breadth ; the anterior ambulacra! summit very near the anterior border ; the posterior 

 ambulacra meet high up on the dorsal surface near the middle of the test, and at a 

 considerable distance from the vent. 



Formation.— Go'csXiim d'Echaillon (Isere) ; very rare. 



Collection. — Dr. Albin Gras. 



