NODULARIA 1043 
situated subcentrally ; dorsal margin slightly arched; ventral 
margin gently curved; anterior side flattened, bluntly rounded ; 
posterior side very obtusely angled; left valve bearing a car- 
dinal, jagged lamelliform tooth; anterior teeth wedge-shaped, 
with jagged edges; posterior teeth fine, elongate, smooth; in- 
terior of shell pale flesh-color, changing towards the anterior 
and posterior margins to iridescent livid blue. 
Pons 31-5, lati 4o mm: “(Preston’). 
Type locality, lower Belgian Congo. 
Unio (Nodularia) submigra Preston, Ann. Mag. Nat. Hist., 
(8), 1V, 1960;-p: 8g; pl..tv, fig. 5- 
NopuLARIA VERRUCOSA Haas. 
“Shell elongated, low, rather solid. Anterior end short, 
semicircular; ventral margin at first horizontal, then bent up- 
wards in an obtuse angle to the posterior end; posterior mar- 
gin at first horizontal, then oblique; posterior ridge distinct, 
somewhat biangulate. Beaks slightly prominent, quite inflated, 
situated at 29/100 of the total length. Beak sculpture con- 
sisting of wart-like elevations, which are connected by low 
curves to concentric, wavy wrinkles, which cover nearly the 
whole shell; vertical under the beaks and on the areola, the 
wrinkles become zigzag-shaped, then extend almost straight to 
the posterior ridge, where they bend upwards and extend over 
the posterior slope, gradually becoming weaker, towards the 
beaks, which, however, only the upper ones reach as low 
striz. As a whole, the lower area appears to be quite smooth, 
while the areola is entirely covered with the wavy wrinkles, 
the warts being very close to each other and almost confluent. 
Ligament weak. Hinge delicate; the cardinal tooth of the 
right valve is lamelliform, striate above; both of the cardinals 
of the left valve are also lamelliform, the anterior twice as 
long as the posterior, which stands under the beak; the lat- 
erals begin directly behind the cardinals, are long and some- 
what bent in the middle. The cardinal teeth and the anterior 
half of the laterals are parallel with the axis of the shell. 
Anterior muscular impressions deep; posterior shallow. Nacre 
