58 PALEONTOLOGY OF NEW JERSEY. 



moderately convex at the apical portions, and to have been flattened or but 

 very slightly convex toward the front, with the surface radiated as in the 

 case of the lower valve, but whether the exterior has been lamellose or only 

 simply radiated I have not been able to ascertain. 



The figure given of this species by Dr. Morton, as cited above, is 

 nearly circular in outline. Among the few casts which I have seen and 

 one perfect lower valve there is none of that form, all being elongate-ovate, 

 narrow toward the beaks and widened below, and all slightly curved to one 

 side. On the casts the muscular imprint as shown on the lower side is 

 quite large and uniform, and situated rather below the middle of the valve. 



The large entire valve of the species figured is neatly perforated 

 through the solid part of its substance, showing the work of some boring 

 moUusk. 



Formation and locality. — In the Lower Green Marls at Upper Free- 

 hold, Monmouth County, N. J., collected by Dr. Bruere. 



Genus DIANCHOEA, Sowerby. 

 (Mineral Conch., Vol. I, p. 183.) 



The genus JDianchora was described by Sowerby in 1815 (Min. 

 Conch., Vol. 1, p. 183), for the reception of two forms of Spondylus-like 

 p hells, that appeared to be without hinge area or teeth. Subsequently the 

 genera Pedopsis Sow. and Pachytes Desh. were proposed by their respective 

 authors for similar forms. In later years all these genera, which appear to be 

 synonyms of each other, have been condemned by many authors, under the 

 impression that the shells on which they were founded were mutilated 

 specimens of Spondylus that had by accident been deprived of th^se parts. 

 It seems strange that naturalists are so often led to discredit the statements 

 of good observers, and to reject their work simply because they themselves 

 have not observed the same features. It is perhaps, however, well that 

 such care be exercised to keep down names and divisions founded upon 

 imperfections and abnormal features. But in this case the rejection has 

 certainly been too hastily made, for the species here described certainly 

 agrees in character perfectly with Sowerby's description and figures, es- 



