180 



WEST COAST SHELLS 



white, decorated with double spiral bands of dark 

 brown, accompanied with spiral grooves. The At- 

 lantic Purple,^. lapUlus, exhibits similar variations. 



T^liais I'lnia^ Mart., the Grooved Pur- 

 ple, {Purpura lima)^ Figure 169, is 

 more rarely met with than the last spe- 

 cies, probably on account of its living 

 in deeper water. The shell is com- 

 monly larger than that of the last spe- 

 cies, while in appearance it is more 

 smooth and symmetrical. The spire 

 consists of four whorls, separated by 

 distinct sutures. The distinguishing 

 feature, however, and the one which gives the name 

 to the shell is the presence of about fifteen spiral 

 grooves on the whorls, giving its surface somewhat 

 of the appearance of a coarse file. The operculum, 

 as in all of the Purples, is thin, horny, and some- 

 what oval in shape. This is a very distinct species, 

 and may be easily recognized by its rounded and 

 channelled whorls. In northern waters the speci- 

 mens are somewhat more similar to the last species, 

 but a little care will easily separate 

 them. 



Another Purple, which lives in San 

 Francisco Bay, but is more highly de- 

 veloped a few hundred miles to the 

 northward, is named T^Juns lamellosa^ 

 Gmelin, the Wrinkled Purple, {Pur- 

 pura crispata). A rather poor figure 

 of a small specimen is shown in Fig- 

 ure 170. Specimens from Puget Fig. 170. x 3 



