Dall.] 240 [March 16, 



base of caudal. Dorsal 22 or 23; anal 21 to 23. Eye very slightly 

 smaller, under jaw slightly larger and fin rays slightly thicker than 

 in E. lonyirostris. 



From the above summary of characters it will be noticed that the 

 only prominent ones by which the two species can be separated, are 

 the deeper body and slightly larger fin rays of E. macrorJiynchus, 

 and these may prove to be only of sexual and not of specific im- 

 portance. When a larger number of specimens have been examined, 

 these differences may prove to be simply individual variations. 



Note. Since communicating the above to the Society, the inval- 

 uable " Zoological Record" of Dr. Giinther, for 1868 (just received 

 in this country) , has called my attention to the " Repertorio Fisico- 

 Natural de la Isla de Cuba," by Prof. Poey, in which, p. 383, he 

 describes as new Euleptorliamphus velox, from Cuba. 



Prof. Poey compares his species with the figure and description of 

 Valenciennes' Hem. lonc/irostris, with which he states it to be very 

 closely allied. He gives depth of body as contained ten and one 

 third times in the length, and the diameter of the eye three and one 

 half times in the head. Dorsal 19; anal 21. Teeth tricuspid. 



These points, from the description of Poey, indicate his specimens 

 to be intermediate between what I have considered above as E. loh- 

 girostris and E. macrorliynchus, and strengthen my belief that there is 

 only one known species of the genus. — F. W. P., March 18th. 



Revision of the Classification of the Mollusca of Mas- 

 sachusetts. By W. H. Dall, Smithsonian Institution. 



The classification here presented is not original with the writer, 

 but simply contains the results of special students in all branches of 

 malacology, published during the last ten years, and systematically 

 arranged in this list. Such a rectification has long been demanded, 

 especially by those students who are removed from large libraries, 

 and who have hitherto been obliged to rely upon the systems of the 

 older authors, which, in the rapid advance of science, are becoming 

 obsolete. For economy in space and convenience to the student, 

 reference has been made to the pages of the new edition of Gould's 

 Invertebrata of Massachusetts, in which the various species here re- 

 ferred to the several genera, are described at length. No attempt 

 has been made to rectify the specific synonymy, except in a very few 

 instances, where it seemed to be urgently required. Doubt as to the 

 value of a genus, or the proper reference of a species to it, or to the 



