150 The Molluscan Family Planorbidae 



Subgenus PLANORBELLA Haldeman, 1842 

 Type by original designation Plnnorbis campanulatus Say 



1842. Planorbella Haldeman, Mon. FW. Univ. Moll., Physidae, p. 14. Type Planorbis 



campanulatus Sa}' (plate 1, figs. 7-11, 1844) 

 1861. Adula H. Adams, Proc. Zool. Soc, p. 145. Type Planorbis midtivolvls Case. 



Non Adula H. and A. Adams, 1857 

 1865. Planorbella Binxey, L. FW. Sh. N. A., II, p. 109. Type Planorbis campanulatus 



Say. As subgenus 

 1865. Adula Binney, op. cit., p. 111. Type Planorbis midtivolvis Case. As subgenus 



1869. Ancaeus H. Adams, Proc. Zool. Soc., p. 275. Non Ancacus Fauvel, 1863. In place 



of Adula, preoccupied 



1870. Planorbella Dall, Ann. Lye. Nat. Hist. N. Y., IX, p. 351. Tj'pe Planorbis 



campanulatus Say. As subgenus 



1870. Adula Dall, op. cit., p. 351. Type Planorbis multivolvis Case. As subgenus 



1870. Planorbella Tryon, Contr. Hald. Mon., pp. 188, 196. Type Planorbis campanu- 

 latus Sa.y. As subgenus 



1870. Adula Tryon, op. cit., pp. 188, 197. Type Planorbis multivolvis Case. As sub- 

 genus 



1883. Planorbella Fischer, Man. de Conch., p. 509. Type Planorbis campanulatus Say. 

 As section of Planorbis 



1883. Adula Fischer, Man. de Conch., p. 509. Type Planorbis multivolvis Case. As 



section of Planorbis 



1884. Planorbella Tryon, S. and S. Conch., Ill, p. 106. Type Planorbis campanulatus 



Say. As subgenus 



1884. Adula Tryon, op cit., p. 106. Type Planorbis multivolvis Case. As subgenus. 



1886. Adula Clessin, Conch. Cab., XVII, p. 33. Tyjie Planorbis multivolvis Case. As 

 subgenus 



1886. Planorbella Clessin, op. cit., j). 33. Type Planorbis campanulatus Say. As 

 subgenus 



1902. Planorbella F. C. Baker, Moll. Chi. Area, II, p. 294. Type Planorbis campanu- 

 latus Say. As subgenus 



1905. I'lanorbella Dall, Alaska Moll., pp. 81, 85. Type Planorbis campanulatus Say. 

 As section of subgenus Helisoma 



1912. Planorbella Hannibal, Proc. Mai. Soc. London, X, p. 159. Type Planorbis 

 campamdatus Say. As subgenus 



1918. Planorbella W.\lker, Miscel. Pub. Mus. Zool., Univ. Mich., No. 6, pp. 12, 94. 

 Type Planorbis campanulatus Say. As subgenus 



1921. Planorbella Germ.\in, Rec. Ind. Mus., XXI, pp. 7, 66. Type Phniorbis cam- 

 panulatus Sa3\ As subgenus 



1926. Planorbella F. C. Baker, Trans. Wis. Acad. Sci. Arts, XXII, p. 202. Type Pla- 



norbis campanulatus Say. As subgenus 



1927. Hypsogyra Lindholm, Trav. Com. I'Etude Lac Baikal, II, p. 181. New name 



for Adula H. Adams, 1861, preoccupied 



1928. Planorbella F. C. Baker, Fresh-water Moll. Wis., I, p. 345. Type Planorbis 



campanulatus Say. Radula and genitalia. As subgenus 



1931. Planorbella F. C. Baker, Proc. Zool. Soc, p. 586. Type Planorbis campanulatus 

 Say. Genitalia and radula. As subgenus 



1931. Adula F. C. Baker, op. cit., p. 566. Type Planorbis nudtivolvis Case. As syn- 

 onym of Planorbella 



1931. Hypsogyra Thiele, Hantlbuch, Teil 2, p. 479. Type Planorbis multivolvis Case. 

 As section of Planorbis 



1931. Planorbella Thiele, Handbuch, Teil 2, p. 479. Type Planorbis campanulatus 

 Sa.y. As section of Planorbis 



Shell. Sinistral, of medium size, resembling Pierosoma in general form 

 but the last whorl notably restricted behind the aj^erture which is campan- 



