184 WEST COAST SHELLS 



ish word meaning "3. spiral staircase." It has long 

 been in use in literature, and it very properly takes 

 the place of the old name, Ladder-shell, which itself 

 was derived from the names Scala and Scalaria^ both 

 of which have now been laid aside. 



Yjpitoniuni hellastriatutn^ Cpr., {Scala bellastriata)^ 

 the Striped Wentletrap, is easily identified from the 

 fact that between the varices fine spiral ridges may 

 be seen, winding upward toward the apex. The 

 spire is short, the last whorl quite large, the varices 

 very numerous, and the sutures so deep that they 

 almost entirely separate the round whorls. The 

 length of a grown specimen is 15 mm. My shells 

 came from San Pedro, but it is also reported from 

 Monterey. 



Epitonium crehricostatum^ Cpr., {Scala crehricos- 

 tata), the Close-ribbed Wentletrap, has a white, pol- 

 ished shell, with about fifteen sharp, thin, reflexed 

 varices to a whorl, which form a kind of crown at 

 the shoulder. It is about the same size as the last 

 species, and it is found from Monterey to San Diego. 



Epitonium {Arctoscala) greenlandicum^ Perry, 

 the Arctic Wentletrap, has a larger and more solid 

 shell. A specimen from Wrangel, Alaska, measures 

 over an inch in length, and is nearly half an inch in 

 diameter at the base. The shell is dull gray in color, 

 strongly marked with spiral ridges, while the low, 

 solid reflexed varices number about nine to the whorl, 

 and the whorls are as numerous as the varices. 



Out on the wide ocean lives the Violet Snail, 

 Janthina exigua^ Lam. It is kept at the surface by 

 a singular raft which it secretes, and it feeds upon 



