32 University of Michigan 
Vanatta says that U. pusillus Lea, ’40, is preoccupied by 
Unio pusilla Raf. ’20. However, as Walker has pointed out, 
the latter was published as Obliquaria pusilla, and thus does 
not invalidate U. pusillus. 
LASTENA LATA (Rafinesque), 1820 
Type locality: Kentucky River. 
Anodonta (Lastena or Hemistena) lata Rafinesque, ’20, p. 317, pl. 
82, f. 17-18. ; 
Unio dehiscens Say, ’29, p. 308. 
Unio oriens Lea, ‘31 (not 34 as stated by Simpson), p. 73, pl. 6, f. 5. 
Odatelia radiata Rafinesque, ’32, p. 154. 
Anodonta lata Raf.=U. dehiscens Say=U. oriens Wea, Conrad, 
"34, Dp. 70. : 
Hemilastena dehiscens (Say), Agassiz, ’52, p. 50. 
Lastena lata (Raf.) = Odatelia radiata Raf., Simpson, ’oo°, p. 654; 
"14, PD. 453. 
Lastena lata Raf. = Hemtstena lata Raf., Frierson, ’14*, p. 7. 
Lastena lata Raf., Vanatta, 15, p. 554 (“type” examined) ; Walker, 
mISe =p: 175. 
, 
There is no dispute over the specific name. However, Utter- 
back (16, p. 104) uses the generic name Lastena for shells 
of the type of Anodonta (Lastena) ohioensis Raf., supposed 
to be identical with Anodonta imbecillis Say, and Herrmannsen 
(47, p- 577) has designated A. ohioensis Raf. as the type of 
Lastena. 
But it is utterly impossible to positively recognize A. ohio- 
ensis as the same species as A. imbecillis (which see), and A. 
ohioensis thus being not identifiable, the generic or subgeneric 
name Lastena cannot be transferred to it, and Simpson was 
bound to use it, as he did, for Jata, the names Hemistena Ratf., 
Odatelia Raf., and Hemilastena Ag. becoming synonyms to it 
(see also Walker, ’18*, p. 4). 
