342 Bulletin American Museum of Natural History (Vol. LIII 
Corbicula nyassana BoureuienaT, 1889, Bull. Soc. Malacol. France, VI, p. 37; 
based upon C. radiata E. A. Smith, 1877, Proc. Zool. Soc. London, p. 718, from Lake 
Nyasa; according to Germain, 1906, Bull. Mus. Hist. Nat. Paris, p. 307, this is not 
separable from C. radiata. 
This species appears to extend from the mid-Nile throughout the region of the 
Great Lakes, southward to Potchefstroom, Transvaal, and westward to Stanleyville. 
Lake Albert: (S. Baker Coll.; Schubotz Coll.) ; near Kassenje (Stuhlmann Coll.). 
Lualaba River at Kindu; Luapula River at Kasenga (J. Bequaert Coll.). | 
The species has been repeatedly recorded from Lake Edward: (Schubotz Coll.); 
near Kasindi and fossil near Vichumbi at 5 m. above the present level of the Lake 
(Gromier Coll.); near Kishakka on the northwestern coast and subfossil near Kata- 
renge on the southwestern coast (Stuhlmann Coll.). We suspect that the specimens 
in question all belonged to our C. radiata edward. 
The recordsfrom Lake Tanganyika probably all pertain to C. tanganyicensis Crosse 
a b (6 a, 
Fig. 72. a-d, Corbicula radiata (Philippi). a-b, Nile, and c-d, White Nile. x2. 
Stanleyville in the Lualaba (Lang and Chapin Coll.). Kachiobwe 
in the Luapula (Stappers Coll.). 
Two specimens from Stanleyville are rather small: length, 13.3 mm.: 
height, 11 mm.; diameter, 7.3mm. They lack the violaceous beak-ray 
of the typical form. Epidermis dusky olive. 
Nine specimens from the Luapula at Kachiobwe are separable into 
two forms. In the more triangular form (Fig. 7la-c) the strong ribs fade 
out on the posterior third of the shell, the hinge-line is wider and the 
lateral teeth lie at a smaller angle than in the other more oval form. The 
color is ecru-olive, in large part suffused with brown. 
Length, 16.4 mm.; height, 14.83 mm.; diameter, 11.0 mm. 
In the more oval form (Fig. 71d-f) the ribs occupy little more than 
half of the valves. The color is ecru-olive. Hinge-plate narrow. 
Length, 16.4 mm.; height, 13.4 mm.; diameter, 10.7 mm. 
In both forms the whole posterior end is densely, very finely covered 
with epidermal laminz, there is no trace of a violet beak-ray, the whole 
eroded beaks being violet, and the interior deep violaceous. 
In one example there is no smoothish posterior. area, and the shape 
is intermediate between the above described specimens. 
