MUSEUM OF COMPARATIVE ZOOLOGY. 357 
APPENDIX. 
Arionta intercisa, W. G. Binx. Mr. Henry Hemphill has lately sent me 
alcoholic specimens of this species, collected by him at San Clemente Island, 
California. 
The jaw is as usual in the genus, with six separated ribs. 
The lingual membrane is as usual in the genus, Teeth 31-1-31, with about 
15 laterals on each side. The extreme laterals only are bicuspid. 
The genitalia are like those figured by me for Huparypha Tryoni. (See Terr. 
Moll. U. S., V.) 
From the series of specimens sent by Mr. ITemphill, I am inclined to believe 
Arionta redimita to be a variety of intercisa. The original specimen may have 
come from the same locality, Formerly I suspected redimita to be a variety of 
ramentosa. 
NOTE ON THE GENERA OF SLUGS. 
Having had occasion to describe several genera of naked terrestrial mollusks, 
I add here, for the sake of comparison, a list of known genera with their 
generic characters, as far as they can be ascertained. It is difficult to draw the 
line between the slugs and the snails. I have not included Succinea, Helisaga, 
Amphibulima (Pellicula), Vitrinopsis, Vitrinizonites, which have some claim to 
be considered süblimaciform, I have included Binneya and Laconia, which 
should, perhaps, be considered as subheliciform. 
AGNATHA. 
Testacella, Cuv. Animal limaciform, subcylindrical, tapering anteriorly : 
tentacles simple: mantle small, posterior, quite near tail, covered with a 
small external shell: no longitudinal furrows above the margin of the foot, 
and no caudal mucus pore: no distinct locomotive disk : external respiratory 
and anal orifice at the posterior right edge of the mantle under peristome of the 
shell: combined generative orifice behind and below the right eye-peduncle. 
Shell external, rudimentary, imperforate, ear-shaped, with a subspiral, pos- 
terior, umbona nucleus. 
No jaw. 
Lingual membrane with no central tooth ; others aculeate, apex hooked. 
Eastern Europe, Teneriffe, Madeira, 
For figure of animal and shell, see Moquin-Tandon, Moll. Terr, et Fluv. 
de la France. 
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