724 UNIO 
“Unio heres is at first glance extraordinarily like Unio 
suferstes, but, on careful consideration, it can easily be dis- 
tinguished by its form, smaller in front and truncate behind, 
the greatest width being behind the beaks and the less promi- 
nent beaks. The hinge of the two species must also be differ- 
ent, since from the condition of the left valve in U. superstes 
the cardinal tooth in the right valve must be a little stronger, 
lower and split in the middle. 
This interesting species is like the preceding (superstes), 
very closely related to the Slavonic Unio nicolaianus. Only 
a single right valve is before me.” 
UNIO KOoBELTI Neumayr. 
“Shell thin, long egg-shaped, inequilateral, slightly inflated ; 
beaks situated in the first fourth of the length, not prominent. 
greatly eroded; somewhat truncated in front; dorsal margin 
curved, higher behind the beaks, where is the greatest height. 
Ventral margin nearly straight; posterior end small, rostrate. 
Cardinal teeth striate, lamelliform, very. thin; laterals long, 
striate, lamelliform, very feeble. Muscular impressions very 
faint. Epidermis blackish-brown. Nacre white.” (Neu- 
mayr). 
Type locality, Kiu-kiang, Province of Kiang-si, China. 
Unio kobelti Neumayer, Ergebnisse d. Reise Szecheny Ost- 
asien, II, 1808, p. 645, pl. 111, fig. I. 
“Unio kobelti stands rather alone; Unio pfisteri Heude is 
like it in a general way, but in that the beaks are somewhat 
more posterior, the posterior part is keeled, the basal margin 
rounded, but especially it differs in the hinge as the character- 
istic lamelliform cardinal teeth are wanting. Monocondylus 
nankingensis Heude resembles it only in the external surface. 
Pseudodon secundus Heude is like it only in the external con- 
tour ; the hinge is entirely different.” 
UNIO ZAMBESIENSIS Preston. 
“Shell subtrapezoidal, deep rich brown, sculptured, espe- 
cially above, with wavy zigzag ridges and below with coarse, 
