388 THE AMERICAN MIDLAND NATURALIST 
Lasmonos leptodon? (Rafinesque). 
Not Figured. 
1820—Unio (Leptodea) teptodon Rafinesque, Ann. Gen. Sci. Phys. 
Bruxeope 205, bls PE XxXoe: 
1829—Symphynota tenuissima Vea, Tr. Am. Phil. Soc., III, p. 435, 
Ply Sa) Pigs 20: 
This species is listed here on the strength of reports of its 
occurrence in the Mississippi and Neosho Rivers of this State. 
From a shell, (measuring 58x31x14mm.), received from Michigan 
through exchange, the author is able to make comparisons and thus 
concur with the general assumption that it should group under 
Lasmonos. However, superficial observations would group it 
near Lastena ohiensis, but presence of hinge teeth, although not 
well developed, and also different beak sculpture would sufficiently 
separate it. Surely the “‘clear water streams’’ of South Missouri 
may also yield specimens of this species since the same rivers that 
reach up into Missouri are reported to bear it in Arkansas. Scam- 
mon (1906, pp. 304 and 305) reports it for Kansas and Simpson 
describes its general range for the upper Mississippi drainage 
south to the Tennessee River and for Southern Michigan.' 
Genus Proptera Rafinesque. 
1819—Proptera Rafinesque, Monog. An. Gen. Sci. Phys. Brux.;—1900b, 
Simpson, Pr. U.S. Nat. Mus., XXII, p. 566, (as sub genus); 1912b, Ortmann, 
An, Car Mus.) Vill, 332) 
(Type, Unio alatus Say) 
ANIMAL CHARACTERS :—Branchial opening with dense papillae; 
anal crenulated; supra-anal small, moderately closely connected 
to anal; inner laminae entirely connected to visceral mass; palpi 
only slightly antero-dorsad; marsupia reniform occupying pos- 
terior part of outer gills, consisting of several ovisacs; conglu- 
tinates not solid, broken; glochidium ax-head or celt-shape, 
usually armed with two spines at each corner of ventral edge of 
each valve; mantle border antero-ventrad to branchial opening 
slightly lamellar with crenulations only. 
SHELL CHARACTERS:—Shell subelliptic or subovate, solid to 
thin, strongly alated post-dorsad; disk smooth; hinge fairly well — 
* The presence of L. leptodon in Missouri need not be so questionable 
now because of A. A. Hinkley’s recent report of it in the James River at 
Galena this State. (Dec. 23, 1915, Pr. U. S. Nat. Mus., Vol. 49, p. 588.) 
