Jaw and Lingual Dentition of Puhnonata. 179 



Helix Ayresiana, Newc. (Arionta). 



San Miguel Isl., California. Mr. H. Harford. 



Genitalia as in H. Traski (see Ann. Lye. N. H. of N. Y., XI, 30, pi. 

 vi, fig. 4). The flagellate extensions of the vaginal prostate beyond 

 the bulbs in this species are, however, much shorter and stouter. 



Helix exarata, Pfr. (Arionta). 



Alameda Co., Calfornia. Dr. L. G. Yates. 



Genitalia as in H. Nickliniana, Proc. Ac. Nat. Sc. Phila., 1874, pi. iv, 

 flg. 3. 



Helix Diabloensis, J. G. Cooper. (Arionta). 

 Alameda Co., California. Mr. L. G. Yates. 



Jaw as usual in the genus, (see Proc. Phila. Ac. Nat. Sc, 1875, 216), 

 with 5 ribs. 



Lingual membrane (pi. xv, flg. G), as usual in the subgenus. The 

 central and first lateral teeth have no side cusps or cutting points ; these 

 appear on the 13th tooth. The 18th tooth has its inner cusp bifid; there 

 may, therefore, be said to be 17 laterals. The marginals (see figure for 

 the last one), are low, wide, with one inner, long, oblique, bifid cutting 

 point, and one outer small cutting point. There are 37-1-37 teeth. 



Genitalia as in H. exarata. 



Helix arrosa, Gould (Arionta). 



Plate xii, fig. 5, gives the genital system. 



The penis-sac is extremely long and gradually tapers into a flagellum. 

 It receives the retractor muscle beyond the middle of its length, and the 

 vas deferens at three-quarters of its length from the vagina. The genital 

 bladder (g. b.) is very small, oval, on a very long duct, which has a very 

 long, stouter, accessory duct (a. d.). 



From H. Nickliniana, H. arrosa diners greatly in the total want of the 

 peculiar accessoi'y organ, probably a vaginal prostate, which characterizes 

 that species (see Phila. Proc. 1874, 41, pi. iii, fig. 4). From H. Toion- 

 sendiana, it still more widely differs (see same, 1873, 254, pi. i, flg. 4), in the 

 character of the penis-sac and genital bladder. 



Helix facta, Newc. (Arionta). 



Sta. Barbara Island, California. Mr. H. Hemphill. 



In my account of the dentition of North American Land Shells in Proc. 

 Phila. Ac. Nat. Sc, 1875, I was unable to include this species. 



