582 UNIO 
Unio ABYSSINICUS von Martens. 
Shell solid, irregularly ovate or subtriangular, inflated, in- 
equilateral; beaks full and high, sculptured with a few smal! 
tubercles; hinge line curved; anterior end rounded; base line 
evenly curved, full at or behind the middle in young shells, be- 
coming nearly straight in old ones; posterior ridge full, slight- 
ly double below, ending below the median line in a narrow, 
faint biangulation; surface lightly, concentrically sculptured, 
the anterior part roughened, the dorsal slope with a few broken 
plications ; epidermis olive-yellow, with obscure bands ; pseudo- 
cardinals strong, multisuleate; laterals solid; nacre flesh-col- 
ored. 
Length (adult) 70, height 43, diam. 32 mm. 
Length (young) 56.5, height 38.5, diam. 28 mm. 
Frana Lake, Abyssinia. 
Unio abyssinicus VON Martens, Mal. BL, XIII, 1866, p. 102.— 
Jicketi, Faun: Moll N[OFAL 1874p: 278) ple ieanoes. 
pl. x; fie} To: 
Nodularia abyssinica SIMPSON, Syn. 1900, p. 826. 
A decidedly heavy shell, which appears to be close to U. 
dembee but is shorter, more solid and somewhat triangular. 
In the young shells the base is well rounded and the general 
outline is at most regularly oval, but the base line becomes 
almost straight with age and it is quite probable that very 
old shells may have the posterior point drawn down a little. 
Jickeli refers this species to Unio habessinicus Henglin, in 
Reise nach Abess., p. 290. This publication is not accessible 
to me and [ do not know whether this is a mere nomen nudum 
or if it be accompanied with a description. von Martens de- 
scribes it as a new species in the Mal. Blatter under the name 
of abyssinicus. 
Unio MONcET! Bourguignat. 
Shell somewhat elongated, rhomboid, inflated, subsolid, 
quite inequilateral; beaks only moderately full, with strong 
zigzag sculpture; surface rather strongly concentrically sculp- 
tured; posterior ridge full, narrowly rounded, curved, ending 
