126 AMERICAN JOURNAL 



name was accompanied with a diagnosis or remarks of any kind, 

 and their extent are only determinable by their contents and the 

 synonymy given of the included species. 



Lamarck subsequently (in 1799) subdivided the same Linnasan 

 genus, reserving the n^me Strombus for the species with a simple 

 alated lip, and bestowing that of Pterocera on those character- 

 ized by a digitated labrum, (excepting, however, the *S'. pespele- 

 cani and S. fusus) each genus being circumscribed and defined 

 by an appropriate diagnosis and reference to specific types. 

 The Strombus lambis of Linne was named as the type of Ptero- 

 cera. The genera thus limited were, as is well known, very 

 generally accepted by succeeding naturalists, and without modi- 

 fication for a long period. 



In 1851, however. Dr. 0. Mbrch, in the catalogue of the Yoldi 

 collection, while retaining the name Pterocera in the Lamarckian 

 sense, subdivided the group, but without accompanying diagnoses, 

 or limitation by any remarks, into three subgenera, for which 

 he adopted the Kleinian names Harpago, Millipes and Hepta- 

 dactylus ; he included in the first the '•'■ chiragra," and " ar- 

 thritiea,'' as well as '"'• pseudoscorpio ;'' in the second ^^ millijjeda" 

 and ^^ scorpiiis ;" and in the last " lambis " and its near associ- 

 ates. The association of ^\pseudoscorpio " with '•'• cldragra" 

 and ''^rugosa," was perhaps inadvertent, the result of a printer's 

 error or a lapsus calami. The brothers Adams, with the amend- 

 ments so required, accepted the three subgenera, and at the 

 same time supplanted the name Pterocera by Harpago, as that 

 of the including genus. The "genus " Avas defined so as to in- 

 clude all the species ; the " ^uh-gQxxxx.^ Millipes^ Klein," was char- 

 acterized by the " outer and inner lips corrugated, digitations of 

 outer lip numerous," and the "sub-genus Heptadactylus., Klein," 

 by the " outer and inner lips smooth ; digitations not numerous ;" 

 the typical sub-genus was not defined, and would therefore re- 

 ceive the residuum,* covered by the generic diagnosis, and eli- 

 minated by the diagnoses of the otiier sub-genera — a course con- 

 ducive to economy of time and thought, but of doubtful expe- 

 diency. 



A still diff"erent association of species has lately been pro- 

 posed by Mr. Gabb (American Journal of Conchology, iv, li^9), 

 who has also adopted the Lamarckian genus in its integrity, and 

 with the same limitation by diagnosis as Lamarck had provided, 

 but he has subdivided it into two subgenera, Pterocera and the 

 " sub-genus JiiV/zpes, H. & A. Adams," distinguishing the latter 

 by the " margins of aperture transversely wrinkled and corru- 



* Such a residuum would include a large number of extinct forms, some 

 of which have been actually referred to the genus by Cheuu. 



