190 WEST COAST SHELLS 



shaped, the canal long and somewhat curved back- 

 ward, and the operculum is oval and horny. There 

 are large white teeth inside the outer lip. The epi- 

 dermis is brown, the shell white, and the varices 

 give the whole a somewhat triangular aspect. Its 

 length is three and a half inches. It was taken, 

 October, 1907, in the outer San Pedro Bay, from 

 water forty feet deep, and it was living when cap- 

 tured. It greatly resembles T^riton corrugatum^ Lam., 

 which lives in the Mediterranean Sea. It is interest- 

 ing to know that quite a large number of other shells 

 from our coast closely resemble Mediterranean spe- 

 cies. This shell was named in honor of Dr. R. H. 

 Tremper, of Ontario, Cal., the owner of the unique 

 specimen, who has kindly deposited the same in the 

 National Museum. 



Another of Dr. Tremper's rare specimens is Triton 

 gibbosus^ Brod, the Gibbous Triton. This shell has 

 five whorls, the suture is extremely deep, the spiral 

 ridges finely beaded, the aperture nearly circular, 

 the canal long, nearly closed, and curved backward. 

 There is no epidermis, the color of the shell is dark, 

 while the varices are brown and white. Its length 

 is two and one-fourth inches and its breadth is one 

 inch less than its length. 



Gyrinium californicu?n, Hds., California Frog- 

 shell, {Ranella calif ornica)^ is well represented in 

 Figure 182. This fine shell is more common in the 

 south, though some excellent specimens have been col- 

 lected in Monterey Bay. The shell is very strong and 

 solid, and on its surface are many knobs and ridges. 

 It appears to grow forward about half a whorl and 



