124 Bulletin American Museum of Natural History [Vol. LIII 
Planorbis stanleyt E. A. Smith 
Planorbis stanleyi E.. A. Smiru, 1888, Proc. Zo6dl. Soc. London, p. 55. J. THIELE, 
1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. (1907-08),’ IIT, p. 209. 
Lake Albert: originally described from that lake without more definite locality; 
Kassenje (Schubotz Coll.). 
This is perhaps a synonym of P. adowensis Bourguignat. 
Subgenus Gyravutus J. de Charpentier 
Planorbis subgenus Gyraulus ‘‘ Agassiz’’ J. DE CHARPENTIER, 1837, Neue Denk- 
schr. Allg. Schweiz. Ges. Naturw., I, ‘Cat. Moll. Terr. Fluv. Suisse,’ p. 21. Type by 
designation of Clessin (1886): Planorbis hispidus Draparnaud=P. albus O. F. Miil- 
ler, one of the species originally included. 
Caillaudia BouRGUIGNAT, 1883, Ann. Sc. Nat. Zool., (6) XV, p. 99. Monotype: 
Caillaudia angulata Bourguignat = Planorbis costulatus Krauss. This is the only 
species mentioned in establishing the genus and as it is correctly defined by reference 
to Jickeli’s figure it must be taken as the type. C. letourneuxi Bourguignat, of Lower 
Egypt, was not described until p. 129 of Bourguignat’s paper and was not mentioned 
on p. 99; moreover, that species appears to be also a Gyraulus and not a Segmen- 
tina as claimed by Pallary (1909, Mém. Inst. Egyptien, VI, 1, p. 58). 
Planorbis subgenus Nautilina Stein, 1850, ‘Leb. Schnecken u. Muscheln Umg. 
Berlins,’ p. 80. Type as fixed by Clessin (1886): Planorbis. albus Miller (as a 
synonym of Gyraulus). 
Shell thin, asa rulesmall, always less than 1 cm. in diameter; flattened as a 
whole and usually more or less angular at the periphery; the whorls few, rapidly or 
very rapidly enlarging, convex above and below. 
According to Annandale and Prashad the radula is as in Planorbis, proper. 
Branchial process simple. Penis relatively long, with a horny stylet; preputium of 
complicated structure; a single retractor muscle present. 
This subgenus or genus is distributed over most of the world. 
The following Ethiopian species appear to belong to Gyraulus. 
Planorbis (Gyraulus) abyssinicus Jickeli=Planorbis abyssinicus JicKE.ti, 1874, 
Nova Acta Ac. Nat. Cur. Dresden, XX XVII, 1, p. 215, Pl. vir, figs. 2la-c. Toquor 
River near Mekerka, Abyssinia. Planorbis (Gyraulus) abyssinicensis GERMAIN, 1922, 
Rec. Indian Mus., X XI, p. 116. 
Planorbis abyssinicus var. gravieri GERMAIN, 1904, Bull. Mus. Hist. Nat. Paris, 
p. 358. Andobed River, Abyssinia. 
Planorbis (Gyraulus) adansoniit J. KE. Gray =Planorbis adansonii J. E. GRAY, 
1850, in M. E. Gray, ‘Figures of Moll. Animals,’ IV, p. 119; based upon Adanson’s 
“le Corot, Coretus,’’ 1757, ‘Hist. Nat. Sénégal, Hist. des Che uillawes: ale. 2 ly.-T, 
fie. 3 Ruder, oneral. 
Plonhorbis (Gyraulus) xthiopicus Bourguignat = Planorbis zethiopicus Bour- 
GUIGNAT, 1888, Ann. Sc. Nat. Zool., (6) XV, p. 99. Planorbis costulatus JickELtI (in 
part), 1874, Nows Acta Ac. Nat. Gite Dreaded KANO TL, 1..py2t9, Pl. var, fies. 23a-c 
(not of Kate Toquor River near Wi elcerkea) peecinia: 
Planorbis (Gyraulus) anderssoni Ancey = Picnoitis anderssont ANCEY, 1890, Bull. 
Soc. Malacol. France, VII, p. 161. Omambonde, Ovampoland. J. etc 1921, 
‘Wiss. Ergebn. Dewinen, Sudpolar Exp.,’ XVI, p. 100, fig. 2. 
