180 NEW WEST AMERICAN SHELLS — BALL. 



Trophon triangulatus Carpenter. 

 (Plato V, Figs. 1, 3, 6.) 



Troplion frianf/ul atu s Ci>r., Suppl. Rep. Brit. Assoc, p. 663, 1863; Proc. Cal. Acad. 

 Sci., Ill, p. 2-24, Feb., 1860. 



Shell large and strong, having much the texture and general aspect 

 of Chorus Belcheri, purplish brown, or nearly the color of Chrysodomus 

 liratus; whorls about seven, the nucleus lost; varices six to the whorl, 

 strong, wide, thin edged, with guttered spines, which have their hinder 

 edge rounded; surface with strongly marked lines of growth and half 

 obsolete fine irregular spiral scratches, strongest on the body and almost 

 wholly wanting between the suture and the spines. The interior of the 

 mouth is polished and white or purplish. The specimen under consid- 

 eration, at a point within the aperture corresponding to the position of 

 the penultimate varix, shows faint indications of short ridges to the 

 number of eight in front of the spine, which look as if that part of the 

 margin of the aperture might in some specimens be denticulate. The 

 specimen measures 75 millimetres long by a maximum diameter (includ- 

 ing the spines) of 50 millimetres. The aperture is 56 millimetres long, 

 inclusive of the open canal, and has a maximum width of 18 millimetres. 

 The siphonal fasciole is strong, with a well marked chink next to it. 



This remarkable shell recalls Chorus Belcheri, from which it differs in 

 the more triangular shape, fewer varices, less rounded body whorl, in 

 the absence of the basal groove and tooth characteristic of Chorus, and 

 probably in the structure of the operculum, which has not yet been 

 observed. It is, of course, a considerably smaller shell than C. Belcheri. 

 The first specimens were dredged by Dr. Cooper in 90 fathoms, near 

 Catalina Island. The description was drawn up from these, though 

 they were less than half an inch long, and were subsequently' generally 

 suspected of being the young of Chorus Belcheri. The present specimen, 

 forwarded for determination by Miss Ida Shepard, of Long Beach, Cali- 

 fornia, for the first time enables one to describe the adult characters of 

 the perfect shell and establish its distinctness as a species. It was col- 

 lected on the sand at Long Beach by Miss L. E. Hale, of Pasadena, and 

 contained the soft parts when fouiul. Miss Hale very generously allowed 

 her " find" to come into the possession of the ]\Iuseum, where it is regis- 

 tered as No. 120,090. 



A second specimen from Long Beach, California, belonging to Mrs. 

 Trowbridge, is younger and somewhat worn. Longitude of shell, 61 

 millimetres; maximum latitude at spines, 40 millimetres; maximum 

 latitude of body, 27.5 millimetres; longitude of aperture, 44 millimetres; 

 longitude of longest spine, 15 millimetres. This specimen resembles the 

 first in color, texture, etc., but shows an obscure i)ale band near the 

 suture. It has six spines to each whorl. The apex is defective, but 

 what remains shows the existence of four whorls in the specimen, with 

 possibly one or two more in the nucleus. The interior of the aperture 



