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 {Lasicna or Hemistena) lata Rafinesqae, '20, p. 317, pi. 

 82, f. 17-18. 



Unio dehiscens Say, '29, p. 308. 



Unio oriens Lea, '31 (not '34 as stated by Simpson), p. 72>, pl- 6, f. 5- 



Odatelia radiata Rafinesque, '32, p. 154. 



Anodonta lata Raf. = U. dehiscens Say = U. oriens Lea, Conrad, 



'34, P- 70. 



Hemilastena dehiscens (Say), Agassiz; '52, p. 50. 



Lastena lata (Rai.) = Odatelia radiata Raf., Simpson, '00c, p. 654; 

 '14, p. 453. 



Lastena lata Rai.:= Hemistefm lata Raf., Frierson, '14*, p. 7. 



Lastena lata Raf., Vanatta, "15, p. 554 ("type" examined) ; Walker, 

 'i8c, 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 

 Laste7ia. 



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 lata, the names Hemistena Raf., 

 Odatelia Raf.. and Hemilastena Ag. becoming synonyms to it 

 (see also Walker, '18", p. 4). 



