730 UNIO 
the Dunker collection labeled “Unio purpuriatus Say, Mexico, 
Anthony,” which agree very well with smaller, scarcely sin- 
uated specimens of Unio aztecorum. He also expresses the 
opinion that “Say’s description . . . basal margin a little 
compressed in the middle and sometimes almost contracted in 
that part,” agrees better with U. astecorum than with U. me- 
dellinus; but as the American conchologists refer Say’s name 
to the latter, I dare not contradict them.” 
Mr. Frierson has recently (1. c.) identified with Say’s species 
a-series of specimens collected by Hinkley in the Valles River, 
near Mecos, Mexico and identified by Dr. Pilsbry as Lampsilis 
strebeli Lea. 
In this connection I am permitted to quote from a note by 
Dr. Pilsbry:: 
“T considered the question of U. purpuriatus Say when 
working on Elinkley’s species and then decided that the descrip- 
tion fits medellinus better than anything else, though I agree 
with Simpson that the case is too uncertain to use Say’s name. 
Of course, it is quite possible that some other species exists, 
which we do not know. but | have a specimen of medellinus, 
which is very close in measurements, and of the right color, 
etc. Hinkley’s shells do not have the rays and none are deep 
purple. I consider them strebeli. U. strebeli is certainly dis- 
tinct from medellinis.” 
It may be added that Fischer and Crosse consider strebeli 
a valid species, while von Martens refers it to astecorum as a 
variety. 
In view of this conflict of opinion, the only thing to do, in 
my opinion, is to still leave the form among the “Species 
mquirende.” 
Unio mMwervensis E,. A. Smith. 
“Shell small, inequilateral, rather thin, narrowly gaping at 
both ends; rounded in front; narrower and produced behind; 
epidermis brownish-olive, with a few, radiating, green lines 
on the posterior portion, smooth, but sculptured with growth 
