6 ANNAL8 NEW YORK ACADEMY OF SCIENCES 



the shell are unreliable, and in all the older works they were considered 

 too unimportant even to be mentioned in the descriptions. In most later 

 works, also, insufficient attention has been given to the character of the 

 protoconch and early conch stages of the shell. For this reason all sug- 

 gestions concerning phylo'geny which are based on figures and descrip- 

 tions alone are to be considered as merely theoretical and as subject to 

 revision, if actual specimens become available. 



Acknowledgments and thanks are extended with pleasure to those who 

 have rendered assistance during the preparation of this paper; to Dr. 

 Carlotta J. Maury for the loan of Oligocenic shells from the Paris Basin, 

 and to Dr. Amadeus W. Grabau for many helpful suggestions The writer 

 desires especially to express her appreciation of the very liberal manner 

 in which Mr. Samuel Henshaw, Director of the Museum of Comparative 

 Zoology, has placed at her disposal the resources of the collection in his 

 care. The following officers of the American Museum of Natural His- 

 tory have also been most generous in providing opportunities for the 

 study of the material in that museum : Dr. Hermon C. Bumpus, Director, 

 and Prof. E. P. Whitfield and Dr. E. 0. Hovey, Curators of tbe Depart- 

 ment of Geology and Invertebrate Paleontology. A^aluable assistance in 

 collecting the literature of the subject has also been given by the libra- 

 rians of both the above mentioned institutions. 



II. Selection of a Genotype for Cerithium sensu stricto 



The selection of a type of the genus Cerithium has given rise to much 

 difference of opinion, and the determination of the proper species to be 

 used as a standard of comparison for other species of the genus has led 

 to a revision of the literature on the subject. 



The name Cerithium was first used by Fabii Columnae [1616] in his 

 treatise, ^'De aquatilibus aliisque nonnulis animalibus." He figures a 

 shell under the name of Buccinum tuberosum, which in his description 

 he says should be referred to "Cerithia." On the margin of the page op- 

 posite this reference are the two names Buccinum tuberosum and Ceri- 

 thium parvum. No description or figure accompanies the latter name, and 

 it is possible that Columns? intended to substitute this name for that of 

 Buccinum tuberosum, for the shell figured on page 53 of his work; but 

 since this is not definitely stated, the specific name tuberosum is retained 

 for the shell figured and referred to Cerithium. Column?e gives no de- 

 scription of the genus Cerithium. and his description of tlie species tuber- 

 osum is meager, but his figure of the latter is sufficiently good clearly to 

 identify his shell with the one described by Lamarqk [1843, p. 292] 



