NATURAL SCIENCES OF PHILADELPHIA. 191 
lingual membrane. I regret not being able to give more accurately 
the characters of the individual teeth,’ but have lost the membrane 
Fig. 38. 
Lingual dentition of S. ineana. 
in removing it for examination. There are 129 rows of 24—1—24: 
teeth each. See Proc. Ac. Nat. Se. Phila., 1874, pl. VIII., fig. 1, 
for figure of dentition of S. decumana. 
(2) Jaw with decided short, vertical ribs to its anterior surface. 
Genus ARION, Fer. 
I have not been able to give any information regarding two spe- 
- cies found within our limits, A. Andersoni (see below, p. 194), and 
A. foliolatus. Indeed there seems so much uncertainty in regard 
to them, that I doubt their belonging to this genus. For fuller 
information, see Ann. N. Y. Lyc. of N. H., X. 297. This leaves 
only one species, A. hortensis, Fér., described and figured in Terr. 
Moll. U.S., and in L. and Frw. Sh. N. A., I., referred to A. fuscus, 
Mull. 
The species was introduced by commerce into Boston many 
years ago. It still exists there,’ specimens having been found by 
me in 1871, from one of which I extracted the jaw and lingual 
membrane here described. I have compared the figures of the 
genitalia of A. hortensis given by Lehmann and A. Schmidt? with 
those given by Leidy in Terr. Moll. U.S. There is a difference 
in the position of the retractor muscle of the penis. Leidy places 
it at the base of the penis sac, Lehmann at the top, Schmidt omitting 
1 Too late for illustration in the text, I have received specimens collected 
by Mr. W. W. Colkett at Key West. There are 27—1—27 teeth, of the 
same type as in P. decumana, referred to in the text. 
2 Specimens can readily be found in gardens between Chestnut and Mt. 
Vernon Streets above Willow Street, as well as elsewhere. 
3 Der Geschlechtsapparat der Stylommatophoren, 1855. 
