174 PROCEEDINGS OF THE ACADEMY OF 



The Limax Ingersolli was received since this paper was com- 

 menced. It has not yet been described. 



Being thus confident of the identity of the species before me, I 

 will proceed to describe their jaws and dentition in detail. 



I have examined the jaw of all the species, finding it to agree 

 with the well-known character of the jaw in the genus. It is 

 arcuate with slightly attenuated, but blunt ends; 

 anterior surface smooth, cutting margin with a 

 decided beak-like median projection. There is 

 often a central vertical carina to the jaw. The 

 ends are often more pointed than in the jaw 



Jaw of Limax. i <> 



figured. 



Limax maximns, Linn. (pi. IV., fig. 4) has about 76 1 76 

 teeth. The centrals have a large, subquadrate base of attachment. 

 The reflection is large, subquadrate, and bears a single stout 

 median cusp, which has a short cutting point, often longer than 

 in the teeth figured ; the side cusps are subobsolete, and bear no 

 cutting points. The lateral teeth, about 18 in number, are like 

 the centrals, but unsymmetrical. The marginal teeth are aculeate. 

 Only a few are simple, as in fig. b, the balance are bifid, as in fig. 

 c. The bifurcation of the marginals commences much nearer the 

 median line than in the specimens examined by Lehmann and 

 Heynemann. There are, indeed, but twelve marginals without the 

 bifurcation on one membrane examined. 



Limax Jlaviis, 1 Linn. (pi. IV., fig. 1). The specimen examined 

 has about 60 1 60 teeth, with 16 laterals. The centrals and 

 laterals are of the same type as in L. maximus, the outer mar- 

 ginals are also bifid. PI. IV., fig. 1, represents the dentition of the 

 species. On other portions of the same membrane the cutting 

 points are longer and sharper. Fig. c represents an extreme 

 marginal. Both of the figures of this species, published by me, 8 

 were drawn from lingual membranes of another species. 



Limax agrestis, 3 Linn. (pi. IV., fig. 3, a. 6. c.) has about 50 1 



1 L. and Frw. Sh. N. A., I. p. 63, fig. 105, is no doubt L. agrestis. Fig. 

 6, p. 285, of Ann. Lye. N. H., N. Y., vol. IX., would more correctly repre- 

 sent the dentition of this species, if the extreme marginals were bifid. 



2 The description and figure given by Morse ( Journ. Portland Soc. N. H. 

 1864, 7, fig. 1) of the jaw of this species could not have been drawn from 

 any Limax, as it is said to be ribbed. The figure of the lingual membrane, 

 also (pi. III., fig. 2), does not give the impression of aculeate marginals. 



3 The figure given of the marginals of L. agrestis, by Lindstrom (Gotlands 



