1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 107 
Fossaria WESTERLUND, 1885, ‘Fauna Paliarct. Binnenconchylien,’ V, p. 49. 
Type: Buccinum truncatulum O. F. Miller. 
Shell in the Afriean forms small, turreted; with a conic spire and an ovate or 
roundly ovate aperture of about half the total length of the shell; the columella not 
twisted. Lateral teeth of radula bi- or tricuspid (in L. truncatula bicuspid; the 
African forms have not been examined in this respect). Genitalia with a very large, 
oblong-ovate or elongate-pyriform prostate; upper section of the penis always shorter * 
than the lower, which is usually very thick. 
The following Ethiopian species appear to belong in this group. 
Lymnexa (Galba) subtruncatula (O. Beettger) = Limnzxa subtruncatula O. BaxrrGER, 
1910, Abh. Senckenberg. Naturf. Ges., XXXII, p. 451, Pl. xxvii, figs. 17a-b. 
Gohabis, Damaraland (subfossil). 
Lymnza (Galba) truncatula (O. F. Miller) = Buccinum truncatulum O. F. Mi1- 
LER, 1774, Verm. Terr. Fluv. Hist.,’ II, p. 180. Limnza peregra Jicknui, 1874, 
Nova Acta Ac. Nat. Cur. Dresden, XX XVII, 1, p. 193, Pl. vu, fig. 9 (mot of O. F. 
Miller). This common European species appears to occur in Abyssinia and 
Eritrea. Bourguignat (1889, ‘Moll. Afrique Equator.,’ p. 157) records it from the 
Vuami River, Tanganyika Territory, but its occurrence there needs to be 
confirmed. 
Lymnxa (Galb1) umlaasiana (Kister) =Limnzus. umlaasianus KtstTer, 1862, 
in Martini and Chemnitz, ‘Syst. Conch. Cab. I, 1, Limnezus,’ p. 32, Pl. v1, figs. 4-5. 
Umlazi River, Natal. Bourguignat, Connolly, and others regard this as a synonym 
of L. truncatula. | ‘ ! 
The occurrence of the true European Lymnexa truncatula in South 
Africa appears beyond doubt and is of some practical importance, since 
this species is a regular intermediate host of the common sheep liver 
fluke (see p. 88). Gilchrist! believes that this snail was introduced 
from Europe by man. “It may be objected,” he says, ‘“‘that it is very 
unlikely that a fresh-water snail could have been imported from Europe 
to South Africa, as the animal itself will not live long out of fresh water, 
and its eggs are readily dried up. A possible explanation may, however, 
be found in the fact that European carp were known to have been intro- 
duced into South Africa at an early time, and it is not improbable that 
fresh water plants and snails were introduced with them, to keep, the 
water fresh and to supply food. There is certainly no doubt that the 
snails could have been introduced at a later date, as even the South 
African Governments have introduced, not only fresh-water fish, but 
also plants and snails from Europe and may thus be unwittingly keep- 
ing up a supply of the dreaded liver fluke.” 
> s 
11918, Parasitology, X, pp. 313-314. 
