188 



PROCEEDINGS OF THE ACADEMY OF 



c extreme marginal) a Charleston specimen. There are 38 1 

 38 teeth, with 11 perfect laterals. 



S. subula, Pfr. (pi. XV., fig. 8, b is an extreme marginal). There 

 are 24 1 24 teeth, with 6 perfect laterals. 



Genus PUPA, Drap. 



I have personally examined the jaw and lingual membrane in 

 only two species, P.fallax (pi. XV., fig 12) and P. rupicola (pi. 

 XV., fig. 2). For information about the other species I am in- 

 debted to Mr. Morse, whose figures are copied below. 



The jaw is low (in P. rupicola, pi. XVI., fig. 7, strongly arched), 



wide, arcuate ; ends but little attenuated in muscorum, penfodon, 



fallax, rupicola ; acutely pointed in corticaria ; a more or less 



developed, broad, blunt median projection to the cutting edge ; 



anterior surface without ribs, but generally witli vertical striae. 



Figure 29 gives a general 

 view of the arrangement of 

 the teeth on the lingual mem- 

 brane. PL XV., fig. 2, shows 

 more correctly the charac- 

 ters of the individual teeth 

 of the genus. The mem- 

 brane is long and narrow, the teeth are as in the genus Vertigo 

 described below ; excepting that in Pupa the central tooth is quite 

 small in proportion to the laterals. The marginal teeth are ir- 

 regularly denticulated, the inner denticle the largest. 



Fig. 29. 



&0& 



0& & ^ 



P. muscorum. [Morse.] 



Fig. 30. 



Fig. 31. 



Lingual dentition of Pvpa pentodon. 

 [Morse.] 



Lingual dentition of Pupa corticaria. 

 [Morse.] 



P. rnuscorum (see fig. 29 above), has 90 rows of 14 1 14 teeth, 

 with six perfect laterals. The figure and description of Lehmann 

 of the European P. muscorum, confirm my belief in the identity 

 of the two forms. 



