108 Bulletin American Museum of Natural History [Vol. LIII 
Subgenus Raprx Denys de Montfort 
Radix Denys DE Montrort, 1810, ‘Conchyl. Systém.,’ IT, p. 266. Monotype: 
Radiz auriculatus Denys de Montfort = Helix auricularia Linneeus. 
Gulnaria “Leach” Turron, 1831, ‘Manual Land Fresh-Water Shells Brit. Isl.,’ 
p. 117 (in the synonymy of L. auricularia). Type: Helix auricularia Linneus, as 
designated by Gray (1847, Proc. Zoél. Soc. London, p. 180; asasynonym of Radiz). 
Neritostoma H. anp A. Apams, 1855, ‘Genera Rec. Moll.,’ II, p. 253. Type: 
Helix auricularia Linnzus. 
~ Shell thin or fragile, broadly ovate or rounded, with a generally short spire of few 
whorls; the last whorl very large, the peristome more or less expanded or even cam- 
panulate. Columella somewhat twisted. Radula with the laterals either all tricuspid 
or partly bicuspid. In the genitalia this group differs from all other Lymnzxe 
in the very long and slender upper sac of the penis which can scarcely be differenti- 
ated from the vas deferens! and not differing much from the lower sac in length. 
The group is indigenous in the Palearctic, Oriental, and Ethiopian 
Regions. 
It is doubtful whether the following list of names of Ethiopian forms 
represents more than one or very few species. Germain? has lately done 
good work in reducing the number of species and figuring many of the 
forms described by Bourguignat. Unfortunately, he fails to point out 
how the six species he retains are to be distinguished. Yet, for the purpose 
of listing the forms, we are accepting most of his conclusions, except in 
the case of L. undussume v. Martens, which is undoubtedly a form o 
natalensis Krauss. 
Limnexa xgyptiaca, L. amygdalina, L. astilba, L. cleopatre, L. expansilabris, L. 
forskali, L. lessepsiana, and L. letourneuxi of Bourguignat (1899, ‘Moll. Afrique 
Hquator.,’ p. 155-156) are nomina nuda, the forms in question having never been 
described nor figured. — 
Lymnzxa (Radix) anceyana (Preston). See p. 118. 
Lymnzxa (Radix) caillaudt (Bourguignat). See p. 118. 
Lymnxa (Radix) caillaudt var. succinoides (Morelet) =Limneus succinoides 
Morstet, 1866, Journ. de Conchyl., XIV, p. 161. Limnzxa bocageana Moretet, 
1868, ‘Voy. Welwitsch, Moll. Terr. Fluv.,’ p. 86, Pl. vit, fig. 3. Limnza benguel- 
lensis MORELET, 1868, op. cit., p. 86, Pl. vi, fig. 4. Limnexa orophila MoreEtxt, 
1868, op. cit., p. 87, Pl. vir, fig. 4. Limnza sordulenta MoRELET, 1868, op. cit., p. 87, 
Pl. vit, fig. 5. Limnea cameront Bourauienat, 1889, ‘Moll. Afrique Equator.,’ p. 
157. Limneza (Radix) africana var. bocagei GERMAIN, 1919, Bull. Mus. Hist. Nat. 
Paris, pp. 183 and 186. Portuguese West Africa (type locality of succinoides: Caroca 
River near Cabo Negro, Benguela). | 
Figures of the genitalia of Radix may be found in L. Soés, 1917, Annales Mus. Nat. Hungarici, XV, 
pp. 21-23. F.C. Baker, 1911, ‘The Lymneide of North and Middle America,’ Chicago Ac. Sci., 
Special Publ. No. 3. Annandale and Prashad, 1919, Rec. Indian Mus., XVIII, p. 40, figs. A, B. 
7L. Germain. 1919. ‘Sur les Limnées africaines appartenant au groupe du Limnza (Radiz) 
natalensis Krauss.’ Bull. Mus. Hist. Nat. Paris., pp. 179-186. 
oe hee Voyage dans |’ Afrique Orientale Anglaise (1912-1913) par G. Babault. Moll. Terr. Fluv.,’ 
