DESCRIPTIONS OF NEW WEST AMERICAN MARINE 

 MOLLUSKS AND NOTES ON PREVIOUSLY DESCRIBED 

 FORMS. 



By Paul Bartsch, 

 Curator, Division of Marine Invertebrates, United States National Museui 



The present paper describes and figures new species of West 

 American mollusks belonging to groups which I have previously 

 monographed. It represents material that has come to hand since 

 the monographs were issued. By far the larger portion of the 

 specimens vvere discovered by the U. S. Bureau of Fisheries steamer 

 Albat7'oss, but many were contributed by private West American 

 collectors, whose zeal and efforts continue to materially increase our 

 knowledge of marine life from year to year. In addition to the 

 descriptions of new forms, references to species (chiefl}' fossil) de- 

 scribed by other authors since the monographs were published have 

 been added, and wherever new information on nuclear characters 

 was available it is stated. 



I had hoped to be able to present with this a new classification of 

 the Rissoidae, but the slowness attending the acquiring of certain 

 material necessary to a complete understanding of the group has 

 decided me not to withhold the manuscript longer, but to publish 

 the data pertaining to members of that famil}'^ under the old familiar 

 designation, reserving the necessary changes for the final revision. 



I wish to express my thanks to all the students who have con- 

 tributed material to this study, acknoAvledgment for which is made 

 under the various species. Credit is due to the photographic divi- 

 sion of the United States National Museum for the splendid en- 

 larged photographs of the species described, and to Mrs. E. B. 

 Decker for the careful and painstaking work of perfecting these 

 illustrations by retouching. 



PYRAMIDELLIDA (LONGCHAEUS) COOPERl Anderson and Martin. 



Plate 42, fig. 3. 

 PyramideUa cooperi Anderson and Martin, Proc. Cala. Acad. Sci., ser. 4, 

 vol. 4, 1914, p. 66, pi. 7, figs. 18a 18&. 



Shell elongate conic, stout, grayish white. All the early whorls 

 decollated, the three remaining strongly channeled at the summit, 

 flattened between the summit and the peripheral sulcus, angulated 



Proceedings U. S. National Museum. Vol. 52-2193. 



637 



