4 University of Michigan 



Pilsbr}' & Rhoads. — Pr. Acad. Nat. Sci. Phil., 1896, p. 494. 

 Knoxville, Tenn. 



Rhoads, S. X. — Xaut., XIII, 1899, p. 48. Lemon City, Fla. 



Smith & Prime.— Ann. X. Y. Lye. Xat. Hist., IX, 1870, 

 p. 402. Huntington, Southold and Greenport, L. I., and Gar- 

 diner's Id., X. Y. 



Sterki, Motor.— Proc. Ohio St. Ac. Sci., Vol. IV, Pt. 8, 

 1907, p. 383. "Over the state." [Ohio.] 



. X'^ote in Naut., XII, 1899, p. 144. Guadeloupe River, 



Victoria Co., Texas. 



Bryant Walker Collection. — Amherst, Worces,ter, and Xo. 

 4993 from ^lass. ; Lime Lake, Staten Id., Gardiner's Id., and 

 Long Id., X. Y. ; District of Columbia; Allegheny, Pa.; head 

 of jMiami River, and X'^ew Philadelphia, O. ; Holston River, 

 Knoxville, Tenn. ; Bearcamp Creek, Bolo, Ills. 



The figures of both the typical dilatattts and the variety 

 given by Binney (loc. cit.) are small and lack details, hence it 

 has been considered advisable to publish the present figures 

 from camera lucida outlines. Planorbis dilatatus was drawn 

 from a specimen loaned by Dr. Walker, X^o. 4993 of his collec- 

 tion, and is from the collection of T. J. Whittemore. Though it 

 has no exact locality it is assumed that it came from Hingham, 

 Mass., and if not one of the original lot mentioned by Gould 

 {loc. cit.) it is at least a topotype. Planorbis d. huchancnsis 

 was drawn from the largest of the Berrien County, Michigan, 

 specimens, evidently a fully adult shell. 



