oon ANNALS OF THE CARNEGIE MUSEUM. 
Lefevre and Curtis, 1910, p. 97, fig. K, where the measurements given 
are: length 0.07; height 0.09; Ortmann, 19114, pl. 89, fig. 19, and Coker 
and Surber, 1911, pl. 1, fig. 2). 
Soft parts whitish. Edge of mantle in the region of anal and 
branchial brownish black. <A black streak runs along the inner edge 
for a certain distance in front of the branchial. 
Paraptera (?) fimbriata (Frierson).” 
A gravid female (with eggs) from Valles River, Valles, San Luis 
Potosi, Mexico, was received from L. S. Frierson (cotype). 
This specimen was collected in December, 1906, or January, 1907, 
and the presence of eggs (beginning of breeding season) in ‘‘ winter”’ 
should be noted. 
I refer this species to this genus only tentatively. The structure of 
the soft parts is in every respect like that of P. gracilis. However, 
other genera have a similar structure. No glochidia were present, 
but the eggs are remarkably small (about 0.10 mm.), and this would 
indicate similarly small glochidia. 
Further there is no doubt that Lampsilis salinasensis Dall (1909, 
p. 181, pl. 30, fig. 3) is the same species. This has been placed by Dall 
in Simpson’s subgenus Proptera on account of shell-characters, and 
there is indeed much similarity of the shells, so that we may regard 
P. fimbriata as a gracilis less typically developed, with a stronger 
shell and better developed hinge-teeth. This species is certainly not 
a typical Lampsilis as shown by the absence of special structures on the 
edge of the mantle. 
Genus PROPTERA Rafinesque. (1819.) 
Simpson, 1900), p. 566 (as subgenus). 
Shell subsolid or rather thin, obovate or subelliptical, strongly 
winged behind, sometimes also in front, inflated or subcompressed, 
without distinct posterior ridge. Disk without sculpture. Hinge- 
teeth generally well-developed. Beak-sculpture much like that of 
Paraptera. Male and female shells slightly different, female more 
developed in the postbasal region. 
Inner lamina of inner gills entirely connected with abdominal sac. 
Edge of the mantle in the temale slightly lamellar in front of branchial, 
49 Frierson, 1907, p. 86, pl. 12. 
50 Hinkley, 1907, p. 68. 
