252 Bulletin American Museum of Natural History [Vol. LIII 
ity ‘and a projection below. Marginal teeth with numerous, long denticles and very 
long body. 
L. Raymond! apparently first observed that Melanoides tubercu- 
lata is viviparous. He stated that the young, newly laid snails spend 
the night inside the shell of the mother snail within a pouch of the neck 
of the animal. Whether all the species included in Melanoides are vivi- 
parous remains uncertain. In opening about a dozen M. wagenia we 
found no embryos. This species has the denticle formula: C. 9, 10, 
OF Lie 1-7 WES and Oth ie AL) 
ene 
a 
| | C 
Fig. 41. Teeth of Melanoides wagenia Pilsbry and Bequaert. At b an inner 
marginal, and at c the outer, drawn in different positions. 
Melanoides is apparently restricted to the Old World tropics, but, as 
its limits have not yet been worked out, its distribution cannot be given 
at present. Yhat of M. tuberculata is shown on Map 2. 
The distribution of Melanoides in Africa is peculiar inasmuch as no 
species are as yet known to occur in Upper Guinea from Senegambia to 
the Gaboon, as also in South Africa proper (Cape Province, Orange 
Free State, and Natal) ; the genus is absent from the basins of ee Senegal, 
Niger, and Orange Rivers. Lake Nyasa has a series of special species. 
The Congo basin seems to nourish many forms, a small part of which are 
probably known thus far; while but few, widely spread forms inhabit 
the river systems of the Nile and Zambezi. 
The following species are at present known from the African con- 
tinent outside of Lake Nyasa: 
Melanoides admirabilis (E. A. Smith). See p. 264. 
Melanoides anomala (Dautzenberg and Germain). See p. 258. 
Melanoides anomala bukamana Pilsbry and Bequaert. See p. 258. 
Se a en SER STAIR RIN Ua la eave aa too eT cone LING i ee 
1Raymond, L. 1852. ‘Recherches anatomo-physiologiques sur les Mollusques del’ Algérie., 
Journ, de Conchyl., III, pp. 325-329. gid q geri 
