2 University of Michigan 



The International Code (Art. 30-e) expressly provides 

 that in designating a type "species which the author of the 

 genus doubtfully referred to it" are excluded. 



For these reasons I am of the opinion that the evident in- 

 tention of the author will be best carried out and the provi- 

 sions of the Code obeyed by considering alata as the generic 

 type and, to save any possible question hereafter, I hereby 

 designate Lyuinadea alaia Sw. {U. alatits Say) as the type 

 of Lymnadea Sw. 



To take the place of the unavailable Symphynota Lea as 

 a name for the subgenus, I propose to substitute Platynaias 

 with Symphynota compressa Lea as the type. The arrange- 

 ment proposed by Ortmann (Naut. XXVIII, 1914, p. 42) 

 will still hold good, but should be reversed as follows : 



Genus Lasmigona Raf. 

 Subgenera Lasmigona s. s. 



Pterosygna Raf. 



Alasminota Ort. 



Platynaias Walk. 



II 



In 1840 Simpson in his Treatise on ^Malacology, p. 382, 

 described a new genus of his subfamily Alasmodontinse as 

 Calceola and gave as the monotype, "C. angulata Sw. Am. Tr. 

 1827, pi. 3 f. I." Both the genus and species seem to have been 

 overlooked by both Lea and Simpson in the preparation of 

 their respective synopses. 



Swainson never actually described a species as Calceola 

 angulata, but his reference is evidently to the Trans. Amer. 

 Phil. Soc. for that year and the species figured on pi. 3, f. i is 

 the Unio cake ol us Lea. It would seem that his generic name 

 was adapted from the specific name used by Lea. Swainson 



