Occasional Papers of the Museum of Zoology 53 
Symph. leptodon Raf. =S. tenuissima Lea= An. purpurascens Sw. 
=U. planus Bar., ’23, Ferussac, 35, p. 25; Conrad, ’36, p. 58, pl. 33. 
Lampsilis leptodon (Raf.), Simpson, ’14, p. 188. 
Leptodea leptodon Raf., Frierson, ’14*, p. 6. 
Lasmonos leptodon (Raf.), Utterback, 716, p. 156. 
Paraptara leptodon (Raf.), Ortmann, 18, p. 571. 
There is no doubt about the specific name Jeptodon Raf. and 
all authors have accepted it. Description and figures are 
entirely satisfactory. 
However, with regard to the validity of the generic name 
Lasmonos Raf., it is important to know what Lasmonos fra- 
gilis Raf., ’31, is. Rafinesque does not quote his Unio (Lep- 
todea) fragilis of ’21 under it, and thus we are to assume that 
it is different. The chief character of this shell is the rudi- 
mentary condition of the cardinal teeth, and this suggests that 
it might be leptodon. However, it fits also certain phases of 
L. fragilis (Raf.), ’20. The rest of the description does not 
clear up matters, since a sub-oval, thin shell, olivaceous out- 
side and purplish inside, fits both species, and the posteriorly 
broader shell with a small wing rather points to fragilis ’20. 
‘ 
The words “some nodulities behind” fit neither. Thus Las- 
monos fragilis is not identifiable and Lasmonos cannot be used 
under any conditions. 
LEPTODEA FRAGILIS (Rafinesque), 1820 
Type locality: Ohio River. 
Unio (Leptodea) fragilis Rafinesque, ’20, p. 295. 
Unio gracilis Barnes, ’23, p. 174. 
Lasmonos fragilis Rafinesque, ’31, p. 5. 
Unio fragilis Raf. =U. gracilis Bar., Conrad, ’34, p. 69; Ferussac, 
220, p25) Conrad, ’36;p. 55, pl. 30; Frierson, “14°, p+, 7- 
Lampsilis gracilis (Bar.), Simpson, 714, p. 181. 
Lampsilis fragilis (Raf.) =L. gracilis (Bar.), Vanatta, ‘15, p. 552 
(“type’”’ examined). 
Lasmonos fragilis Raf., Utterback, 716, p. 152 (quotations in part 
incorrect ). 
