282 



Notes on Lingual Dentition of Molliosoa. 



but it was preserved in the same bottle as Ancylus Newherryi^ 

 Pompholyx effusa, Flaminicola Nuttalliana^ and other species of 

 the Pacific coast. 



Fig. 1. 



Lingual dentition of Succinea M uttalliana, Lea. 



Lino^ual membrane broad. Teeth 19.1.19, in almost straidit 

 transverse rows. Centrals short, stout, obtusely tricuspid, the 

 central cusp with a long acute point, attached to a quadrate plate, 

 the upper edge of which has a central quadrangular spot of thinner 

 texture, easily mistaken for a complete cutting away of a portion 

 of the plate. Laterals on somewhat oblong plates which bear on 

 their outer upper corner a small quadrangular expansion, stoutly 

 and obtusely bicuspid, the larger cusp surmounted by a long 

 acute point; base rounded. Uncini on plates with rounded bases 

 and attenuated and serrated apices, irregularly denticulated. 



Fig. 1, a shows two centrals and two laterals, with a third 

 lateral detached ; h and c show uncini from the left of the median 

 line; d the eighth lateral, partly in profile. 



The jaw of Succinea Nuttalliana has a perfectly smooth an- 

 terior surface. 



Biilimulus pallidior, Sowerby. 



Lingual membrane broad, with numerous nearly straight trans- 

 verse rows of 40.L40. teeth. Centrals with one long blunt 



Lingual dentition of Bulimulus pallidior, Sowb. 



median, and two obsolete, small side cusps; plate subquadrate, 

 rounded at base, excavated at its upper margin, and with small 



