434 Bulletin American Museum of Natural History [Vol. LIII 
Mutela iris, new species 
Plate XLI, Figures 2 and 2a 
Channel leading from Lake Kabamba to the Lualaba River at 
Mulongo. (J. Bequaert Coll.). 
The shell is rather thin, long, the upper and lower margins ee avd, but very 
slightly diverging posteriorly; posterior margin obliquely truncate, bluntly pointed 
near the base; anterior margin rounded. The beaks are low, wide, scarcely project 
above the hinge line, and are far forward, the anterior end being contained 5% times 
in the total length. There is a bluntly angular posterior ridge, which, together with 
the flattened area just below it, is irregularly broken into low, concentric folds, and 
toward the beaks some rather small, irregular, interrupted corrugation; a considerable 
area at the beaks being eroded. The rest of the valve has some very low, coarse 
wrinkles along growth lines. The periostracum is smooth and somewhat glossy in the 
median part, densely and finely laminate posteriorly, above the posterior ridge, and 
to a small extent at the anterior end. The color black toward the margins, shading 
upward into warm sepia, paler toward the beaks. Inside there is a very low, long 
(about 1X5 mm.), rounded anterior cardinal tooth, and under the ligament a long, 
slender ridge in the place of laterals. In the left valve there is no cardinal and the 
lateral ridge is just perceptibly grooved lengthwise. The anterior muscle impressions 
are hardly sunken, but there is a thickened anterior border. The anterior pedal re- 
tractor scar appears to be distinct from, but near, the adductor scar. Posteriorly 
there is a single long scar. The internal color is lavender-gray in the median and lower 
part, a peculiar bronzed reddish above and posteriorly, with conspicuous hessian 
brown and violet stains toward the beak cavity. | 
Length, 98 mm.; ; height at beaks, 27 mm.; posteriorly, 34mm.; diameter, 18 mm. 
This species is similar to Mutela chevaliert Germain in having the 
beaks far anterior. It differs from that, and from M. plicata (E. v. 
Martens) by the more truncate posterior end and stronger posterior 
ridge; and apparently also by the possession of vestigial hinge teeth, in 
which it has some resemblance to Pseudospatha. This genus, however, 
is so unlike our species in other characters that we doubt whether there 
is any direct relationship. 
Mutela hargeri E. A. Smith 
Plate XLI, Figures 3 and 3a 
Mutela hargert EK. A. Smiru, 1908, Proc. Malacol. Soc. London, VIII, p. 14, fig. 
Simpson, 1914, ‘Descript. Cat. of Naiades,’ p. 1357. 
Lake Moero: (type locality; R. L. Harger Coll.). 
Lake Moero off Lukonzolwa (Stappers Coll.). The apebite has also 
been found in the Luapula River, at Kachiobwe and Kasenga, by 
Stappers. 
