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
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