154 PROCEEDINGS OF THE ACADEMY OP 



United States, as Carpenter's was without the animal, and the 

 genus is only mentioned in one Atlantic coast list, as probably 

 found on Long Island, N. Y., by Sanderson Smith, in the Annals 

 N. Y. Lye. Nat. Hist. 1810, though it is suspected that some of 

 the New England " Bissoids" are congeneric. 1 



I have used the specific name Califomica as not likely to lead 

 to any confusion, even if Mr. Tryon's species proves to be a true 

 Hydrobid, and thus of another family. 



EXPLANATION OF THE PLATE. 



A. Alexia setifer. 1, 2. The animals crawling, with shells of different 

 forms and color. 3. Most usual form of the shell, showing the stripes often 

 observed. 4. Var. tenuis, an extreme form. 5. Young, without upper 

 tooth, a form of the shell occasionally found in the adult. 6. Young of 

 very thin variety, showing revolving line of setse. 



B. Limax Heiostoni. Natural size. 2. Caudal extremity. 3. Shell. 4. 

 Jaw magnified. 5. Shield from above showing groove, and generative 

 organ anterior to it. 



C. Limax campestris, var. 2, 3, 4, as in B. 



D. Ariolimax var. Calif omicus. Natural size of parts. 1. Lateral view 

 of furrows behind shield. 2. Caudal extremity, showing furrows, mucous 

 pore and color of foot. 3. Anterior parts from alcohol, showing generative 

 organs. 



E. Ariolimax iiiger. Natural size. 2, 3, 4, as in B. 



F. Avion Andersonii. Natural size. 2, 3, 4, as in B. 5. Lower sur- 

 face of locomotive disk, from life. 



G. Lysinoe Diabloensis. 2. Style of sculpture above. 3. Shell from 

 beneath. 4. Front view of shell. 5. Lower surface of locomotive disk, 

 showing crenations. 



H. Assiminea Califomica, magnified. 2, 3, as in A. 



' Mr. Smith's name " Coecum Cooperi," being pre-occupied for a differ- 

 ent Californian species, I may here return the compliment he offers to the 

 memory of my father by naming it Ccecum SiiiTnu, Cooper. 



