Dentition of Pulmonata. 28 



prominent organ. It enters the vagina at its base. It is as long as 

 the whole system, stout, especially in its lower half, abruptly terminating 

 in an acute point above, where it receives the vas deferens. The latter 

 organ (7) is enlarged for some distance after leaving the penis sac. The 

 retractor muscle (6) of the penis is inserted on the side of the sac, at the 

 lower third of its length. PI. II, fig. IX. 



Helix Troostiana, Lea. {Polygyra.') 

 Kentucky, Mr. A. G. Wetherby. 



Jaw as usual in the sub-genus Polygyra, with about ten, broad, crowded 

 ribs, denticulating either margin. 



Lingual membrane (pi. V, fig. VI) long and narrow. Teeth about 25- 

 1-25. Centrals and laterals quadrate, the former tricuspid, the latter 

 bicuspid, the cusps stout: all the cusps with cutting points. Marginals 

 low, wide, with one inner, oblique, stout, short, bluntly bifid cusp, and 

 one outer, shorter, bluntly bifid cusp. 



Genital system (pi. V, fig. Ill) long and slender, especially the ovary 

 (11), and oviduct (8); vagina long, receiving the duct of the genital 

 bladder below its middle, and the sac of the penis still lower down ; penis 

 long, tubular, of about same width as the vagina, with a prominent bulb 

 at its apex, into the end of which is inserted the vas deferens (7) and at 

 the side of which the retractor muscle (6) is attached ; genital bladder (9) 

 moderate, oval, on a duct (16) of about equal length and size as the vagina. 



Helix obstrieta, Say. (Triodopsis.) 



Ohio, Mr. A. G. Wetherby. 



The genital system resembles exactly that of H. palliata, Say, as figured 

 by Dr. Leidy in Terr. Moll. U. S., I, pi. vii, fig. 8. 



Helix Clarki, Lea. {THodopsis? Mesodon?) 

 Hayesville, N. C, Miss Annie E. Law. 



Jaw as usual, arcuate, ends attenuated, blunt; anterior surface with 

 about fourteen stout, separated ribs, denticulating either margin. 



Lingual membrane long and narrow. Teeth about 35-1-35. Centrals 

 with a stout, short, median cusp, bearing a very short, blunt, cutting 

 point, the outer cusps subobsolete. Laterals like the centrals, but uu- 

 symmetrical. Marginals wide, low, with one, inner, short, broad, sharply 

 bifurcated cutting point, and one shorter, outer, bifurcated cutting point. 

 PI. VI, flg. I. 



The genital system (pi. VI, flg. VI) is peculiar in several respects. The 

 ovary (11) is very slender, and equals about one-half the length of the 

 oviduct. The epididymis (2) is highly developed, greatly convoluted, 

 stout, four times the length of the ovary. The oviduct (8) is convoluted. 



