294 Organic Remains of the Ferruginous Sand Formation. 



A. iellinoides. (S. G. M.) PI. V, fig. 11. Irregular, but most- 

 ly subovate, with concentric undulations. Both these species are 

 common in New Jersey ; the latter resembles Jl. ephippium, to 

 which it is referred in the first part of this Synopsis. 



VENILIA.* (S. G. M.) 



V. Conradi. PI. VIII, fig. 1,2. Trigonal, ventricose, concentrical- 

 ly sulcated ; beaks long and incurved : diameter an inch and a half. 



This singular marine shell, so different from any of the hitherto 

 known genera, was discovered in New Jersey by my estimable friend 

 Mr. T. A. Conrad, under whose name I gladly introduce it to notice. 



ECHINIDE^. 



SPATA.NGUS. 



S. parastatus. (S. G. M.) Same as No. 1, of this Synopsis. See 

 vol. xviii, PI. 3, fig. 10. 



CIDARIS. 



C. diatretim. (S. G. M.) A compressed species, found with the 

 preceding, in the calcareous beds of New Jersey. 



NUCLEOLITES. 



JV. crucifer. (S. G. M.) Referred in the former part of this 

 Synopsis to the genus Ananchytes, and figured, vol. xviii, PI. 3, fig. 8. 



CLTPEASTER. 



C. florealis. (S. G. M.) Noticed generically in the first part of 

 this Synopsis. 



Very convex ; each of the five ambulacra composed of two pairs 

 of finely dotted lines: base subelliptical, concave; margin abrupt. 

 From the blue marl of Delaware. 



To be continued. 



* Generic description. An equivalve bivalve ; hinge with three robust cardinal 

 teeth in each valve, and an elongated, thick lateral tooth on the posterior side, simi- 

 lar to that of Unio : anterior muscular impression profound. 



