Dentition of Pulmonate Mollusks. 113 



Ulerope. 



Merope fringilla, Pfr. Admiralty Island. Prof. A. G. 

 Wetlierby. 



The dried remains of the animal in the shell of a cabinet specimen fur- 

 nished the lingual membrane and jaw here described. The shell is the 

 variety with the pink peristome. 



Jaw with numerous crowded, stout ribs, denticulating either margin. 



Lingual membrane (PI. X, fig. E) long and narrow; teeth 28-1-28, with 

 about 11 laterals. Centrals with base of attachment longer than wide; side 

 cusps obsolete, side cutting points wanting; middle cusp broad, blunt, with 

 a very short, broad, blunt cutting point. Laterals like the centrals, but 

 asymmetrical; the cutting point becomes longer as they pass off laterally, 

 and at the 12th tooth it commences to be bluntty trifid. The marginals are 

 peculiar; their base of attachment is subquadrate, with a single broad cusp, 

 bearing a very broad, oblique, expanding, trifid cutting point; the outer 

 division very small, pointed; the median longer, very broad, squarely trunc- 

 ated ; the inner one about half the size of the median, recurved and sharply 

 pointed. 



The left hand figure in the plate shows a marginal in profile. 



The dentition of this species is peculiar, resembling that common in 

 OrflLCtUcus rather than the type usual in Helix. 



Helix, -* . Costa Pica, Dr. W. M. Gabb. 



Jaw not observed. 



Lingual membrane (PI. V, fig. L) long and narrow. Teeth 15-1-15. Cen- 

 trals with a base of attachment longer than wide, with lower lateral ex- 

 pansions; reflection large, decidedly tricuspid, each cusp surmounted by a 

 cutting point. Laterals like the centrals, but asymmetrical and consequently 

 bicuspid. Marginals low, wide, irregularly denticulated or serrate, the 

 inner three cutting points being longer than the outer ones, of which there 

 are several. 



Helix astur, Souv. I do not know the position of this species. 

 Xew Caledonia. 



Jaw (PI. XVI, fig. B) low, wide, slightly arcuate, ends scarcely attenu- 

 ated, blunt; anterior surface without ribs; a wide, blunt, median projection 

 to the cutting edge; a line of reinforcement running parallel to the cutting 

 margin; a strong muscular attachment to the upper margin. 



Lingual membrane (PI. X, fig. F) with 30-1-30 teeth, nine perfect laterals 

 on each side; teeth as usual in the Helicklcn ; with decided side cusps and 

 cutting points. 



Helix convicta, Cox. Australia. Dr. Cox. 



Subgeneric position unknown to me. 



Jaw highly arcuate, thick, ends blunt; anterior surface with seven sepa- 

 rated, stout ribs, denticulating either margin. 



