PHYLOGENY OF FUSUS AND ITS ALLIES. 7 



collection of that institution, and to Professor W. B. Clark and Dr. 

 George C. Martin acknowledgments are hereby made. 



At Philadelphia the writer was granted every opportunity to study 

 the extensive collections of recent and fossil Fusidae at the Academy 

 of Natural Sciences, and the Wagner Free Institute of Science. To 

 the officers of these institutions, particularly to Professor H. A. Pills- 

 bry, and to Dr. Chas. W. Johnson acknowledgments and thanks are 

 herewith tendered. To the Academy we are also indebted for the 

 loan of specimens from which many of the illustrations of plates 

 XVII and XVIII are made. To the Wagner Free Institute we are 

 indebted for the loan of the original drawings of figs, ii and 12. 

 The original drawings of figs. 4, 9, 10, and 17 were loaned by 

 Professor G. D. Harris, of Cornell University. The free use of 

 the collections of the American Museum of Natural History were 

 granted by Professor R. P. Whitfield and Dr. L. P. Gratacap, curators 

 respectively of palaeontology and of recent mollusca, and to these 

 gentlemen thanks are due. The collections of the palasontological 

 department of Columbia University also contain a valuable series of 

 recent and Tertiary Fusidse. Other acknowledgements are due to 

 the Buffalo Society of Natural Sciences, the Massachusetts Institute 

 of Technology and to many friends for the loan of specimens. To 

 Miss Elvira Wood, of Washington, formerly Instructor in Palaeontology 

 in the Massachusetts Institute of Technology, the writer is greatly 

 indebted for the care and skillful labor she has bestowed on the difficult 

 figures of the protoconchs and early conch stages shown in plates XVII 

 and X\TII, as well as the original figures in the text. 



DESCRIPTION OF GENERA AND SPECIES, WITH A DIS- 

 CUSSION OF THEIR GENETIC RELATIONSHIPS. 



A. 



The Genus FUSUS Bruguiere. 



The genus Fusus is credited by Fisher and Cossmann to Klein 

 (1753) ; by Agassiz and Scudder to Bruguiere (1791), and by Tryon 

 and others to Lamarck (1799). Chemnitz in 1780 and later applied 

 the name to the description of his species without however char- 

 acterizing it gencrically. Bruguiere in 1791, in the Encyclopedic 

 Mctlwdiqiic descrilicd the genus, including in it those species of the 

 Liiincnean genus il/;/rr.r, , which have a fusoid form. Lamarck restricted 

 the genus by retaining in it only those shells, which were characterized 

 by a fusoid or spindle-shaped form, a long canal, an absence of varices, 

 and an absence of colunu'llar plaits. Scluiniaclicr in 1817 and Swain- 

 son in i8_]o still frrther restricted the genus, the former naming as the 



