NATURAL SCIENCES OP PHILADELPHIA. 141 



and it may be only an adaptation to a drier climate. It is quite 

 well shown even in alcoholic specimens, and I am surprised that 

 it has not before been mentioned. Some parts of Mr. W. G. Bin- 

 ney's description may, however, be taken from this variety. The 

 following notes have not before been published, and are all taken 

 from the southern form. Mr. Toy has brought it from the Sierra 

 Nevada, lat. 39, alt. about 3500 feet, but I have not heard of it 

 elsewhere out of the coast range. 



The locomotive disk, anal and generative orifices are like those 

 of Limax. Fig. D, 3, shows the latter as preserved in alcohol in 

 a specimen taken in copulo. I may be able to describe them more 

 fulh' from fresh ones. The mantle is minutely granulated, which 

 may have led Mr. Tryon to place it in Amalia. The dorsal- 

 grooves are unicolor with the rest of body, but those of the upper 

 margin of foot are colored brown (sometimes very pale), the color 

 permanent in alcohol, and the stripes wider at every fourth or 

 fifth, like the grooves. The longitudinal division of the foot be- 

 neath is very faintly perceptible. 



The young, just hatched, is pale^ellowish, with pellucid whitish 

 spots, and when an inch and a half long is colored like adult, 

 while the shell is perceptible through the thin shield. This can 

 also be seen by looking into the grisacle of the adult when fully 

 expanded. 



Eggs are laid from April 1st to June, and vary in size from 0.44 

 X 0.36 to 0.35 x 0.26 inch, (probably laid by slugs of various 

 ages). They have a shelly but tough envelope, and, after they are 

 laid, the shell is often entirely wanting in the animal, having ap- 

 parently been absorbed to form the egg-shells ! This may explain 

 the absence or fragmentary state of the shell in some species re- 

 ferred to Avion. 



ARIOLIMAX NIGER. Cp. n. s. PL 3, fig. E. 1, 2, 3, 4. 



Sp. ch. A. forma, testa, et maxilla ".4. ColumMano" per similio, sed 

 minor, robustior, colore nigro, tentaculis et disco motivo infra pallidi- 

 oribus, maxilla costulis circa xx, dorso non carinato. 



Long. ii. et dim. poll. (65 millimetres.) 



In form, shell and jaw, it resembles A. Columbianus, but is 

 smaller, back rounder, more robust, black, with tentacles and loco- 

 motive disk beneath paler, its jaw with only about 20 riblets. 

 Length 2^ inches. 



