GLASS-SNAIL. 1 53 



Helicodiscus I in eat us. Say, He-li-co-dis'-cus lin-e- 

 a'-tus, has a minute, flattened shell, one-eighth of an 

 inch in diameter, shaped like a depressed, circular 

 disk. Whorls four, visible from below as well as from 

 above. Within the outer whorl may be seen two or 

 three pairs of white, conical teeth. The epidermis 

 is greenish, and numerous fine lines cross the whorls. 

 It lives in many places in the east, and is reported 

 from Oakland, California. 



There remain several mollusks which are either 

 wholly destitute of a shell, or are only partially cov- 

 ered by one that is small or rudiamentary. These 

 animals are called slugs, in distinction from the snails, 

 which bear well developed shells. 



The first one on our list is named Binneya notabilis, 

 Cooper, Bin'-ney-a no-tab'-i-lis. It is found on Santa 

 Barbara Island, and also in Mexico. The body of 

 this mollusk is whitish, with many dark blotches on 

 its sides. The shell is about the size and shape of 

 your little finger nail, spiral at one extremity, and 

 open and flattened at the other. It is of a yellowish 

 horn-color. 



HcmpJiillia glandulosa A Bl. and Bin., Hemp-hill'- 

 i-a glan-du-lo'-sa. 



This curious little slug lives in Oregon and Wash- 

 ington. When extended it is about an inch long. 

 On its back is a hump, and on the hump is a shell, 

 brownish, flattened and scale-like, one-fifth the length 

 of the animal. Its color is white, mottled with dark 

 brown. 



Propliysaou Heuipliilli, Bl. and Bin., Pro-fy'-sa-on 

 Hemp-hill'i. 



Animal slug-like, large and thick in front, tapering 

 behind. The body is of a smoky white color, marked 



