SUPPLEMENTARY NOTES AND OBSERVATIONS. 



387 



*^{h). Pierinea hrisa is undouhtedly Amboni/chia stricpcosta, M'Ciiesney, 

 or Pterinea stricBcosta, W. & M, " This may be true ; but neither the figure 

 of M'Chesney, nor the specimen communicated by Prof. "VVinchell 

 under this name, afford evidence of the fact, and the specimens or casts 

 referred to are not identical with either the figure of M'Chesney or ray 

 own specimen. A specimen in the collection of Prof. Marcy, correspond- 

 ing with the figure of M'Chesney, is a larger shell with stronger ribs, 

 and is different in form. A larger collection is required for a satisfactory 

 determination. The gutta-percha cast, communicated by Prof. Winchell 

 under the name P. stricRcosta^ is a very different species from that figured 

 by M'Chesney, and probably belonging to a different genus. 



" (c). Amphicalia leidiji, Hall, is Ambofiyckia neglecta, M'Chesney, or 

 Pterinex neglecta, W. & M." This species will scarcely be referred to 

 Pterinea, when its hinge structure is understood. The striated hinge plate 

 mentioned by Profs. Winchell and Marcy, and which I have seen 

 through the kindness of Prof. Marcy, appears as if oblique or expand- 

 ing outward, giving space for a strong external ligament, while the 

 large pit beneath the beaks does not ally it very nearly with Pterinea ; 

 and until we know more about it, I shall leave it under its proposed 

 generic name of Amphic(ELIA, though it is scarcely worth while to 

 seek any relation to Leptodomus, which I believe the author of the 

 genus will regard as composed of heterogeneous materials. In regard 

 to identity with P. neglecta, I have been inclined to the opinion that there 

 might be two species of this genus in the rocks of Wisconsin and Illinois ; 

 numerous specimens presenting differences of outline, which are easily 

 recognizable. The accompanying outline figures are, 1, copied from the 

 figure given by M'Chesney ; and 2, from A. leidyi. It may require farther 

 comparison, with larger collections, to demonstrate the identity or dif- 

 ference of these forms. 



1 



" [d). Pleurotomaria axion has been referred by us to P. halei, Hall." 

 Notwithstanding the fact that Prof. Winchell has identified P. axion as 



