172 Jaw and Lingual Dentition of Pulmonata. 



Lingual membrane long and narrow. Teeth about 16 - 1 - 16. Centrals 

 as usual in the Hdicince (pi. xviii, fig. C). The side cusps and cutting 

 points are well developed, the base of attachment longer than wide. 

 Laterals of same type, but unsymmetrical, and consequently only bicus- 

 pid. The change from laterals to marginals. (8th and 9th teeth of figure) 

 is very gradual, there being no splitting of the inner cuttiug points, tit 

 least not as in most species (see pi. xii, fig. E). Marginals (16th tooth of 

 figure) very low, wide, with one inner, long, blunt cuttiug point, and one 

 outer, small, blunt. 



The low, wide marginal teeth of this species are peculiar. 



Helix rufeseens, Pennant (Fruticicola) . 

 Extracted from a dry English shell furnished by Mr. A. 

 G. Wetherby. I include it here because the species has 

 been introduced at Quebec. I was not able to illustrate it 

 when treating of the Lingual Dentition of North American 

 Land Shells, in Proc. Ac. Nat. Sc. Phila., 1875, 214. 



There are 26-1-26 teeth. The characters of all are shown in my fig- 

 ures. It will be seen that the transition from laterals to marginals (16 to 

 19), see also Lehmann, in Malak. Blatt. xvi, is gradual. The inner cut- 

 ting point is not bifid. 



Helix pubeseens, Pfr. (Fraticicola). 



Haiti. Mr. V. P. Parkhurst to Mr. T. Bland. 



Jaw (pi. xv, fig. C) thin, semitransparent, low, slightly arcuate, 

 ends scarcely attenuated, blunt; upper margin with a -strong muscular 

 attachment: no median projection to cuttiug edge; anterior surface with 

 about 20 ribs denticulatiug either margin; these ribs appear in most cases 

 to be broad, flat, with narrow interstices, but iu others there are appear- 

 ances such as I have described in Bulimnlus limnxoidcs (see below). 



Lingual membrane long and narrow (pi. xv, fig. D). Teeth as usual 

 in the Helicinue. The change from laterals to marginals is very gradual, 

 not formed by the splitting of the inner cutting point. The 12th tooth 

 (figured) shows the commencement of the transition. The 22d (figured) 

 is a marginal tooth. The inner cutting point of the marginals is rarely 

 bifid. 



Teeth about 24-1 -24. 



Helix Studeriana, Fer. (Stylodon). 



Seychelles, Consul Pike to Mr. T. Bland. 



Jaw stout, strongly arched, ends but little attenuated, blunt ; anterior 

 surface without ribs ; there are, however, a few, coarse, broad, vertical 



