DIAGNOSES OF NEW SHELLS FROM THE PACIFIC OCEAN. 



By William Healey Dall. 



Curator Division of Mollushs, United States National Museum. 



For several years new species of shells from Northwest America 

 and other parts of the Pacific Ocean have been accumulating in 

 the national collection, and, as some of them have been furnished 

 with manuscript names for the convenience of collectors, it was 

 thought best to prepare diagnoses of some of these species before 

 the manuscript names found their way into print. 



Some of the specimens have long been in the collection, but re- 

 mained unstudied on account of the pressure of other duties; some 

 have been contributed by generous correspondents, and others 

 obtained from various sources. Figures of many of them have been 

 prepared and wUl appear later. 



CHRYSODOMUS EULIMATUS Dall. 

 Chrysodomus eulimatus Dall, Smiths. Misc. Coll., vol. 50, No. 1727, p. 156, July, 1907. 



Shell large, with a thin dehiscent periostracum, and about eight 

 whorls without the (lost) nucleus; shell substance white with the 

 outer layer more or less tinged with rosaceous purple; whorls well 

 inflated, the suture appressed, with a band of minor sculpture in 

 front of it; upper whorls with eight or less rounded prominent 

 flexuous ribs extending from suture to suture, most prominent at 

 the shoulder of the whorl and least so on the presutural band; they 

 become obsolete on the first half of the last whorl; spiral sculpture 

 of three sizes of spiral threads, the larger, of which there are eight 

 between the sutures at the beginning of the last whorl; the second 

 size running in the middle of the wide interspaces between the 

 major cords; and lastly the finer ones which cover the surface of 

 the presutural band and the interspaces between the other threads. 

 All these are crossed by fine rather prominent incremental lines. 

 Aperture elongate-ovate with a wide somewhat recurved canal; 

 body with a thin layer of callus; pillar with a thick white callous 

 border; siphonal fasciole well marked; outer lip thin, simple, sharp, 



Proceedings U. S. National Museum, Vou 45-No. 2002. 



587 



