119 



ADDITIONAL NOTE. 



Since the work on this group of Unios was completed I have had the oppor- 

 tunity to re-examine a carefully prepared paper by Mr. Chas. T. Simpson on the 

 " Unionidfe of Florida." I must dissent from some of the conclusions Mr. Simpson 

 reaches, though in the main he is, beyond question, correct. That author places 

 Unio lepidus Gould and Unio trossulus Lea in the parvus group. Both these shells 

 are here out of place. Unio trossulus has the fine concentric undulations on the 

 umbones which are so characteristic of many Unios typified by Unio fallax, Unio 

 lienosiis et cetera. Both Lea's figure and his description do not permit that this 

 form go into the present group. The character of the radiation, as given by Mr. 

 Simpson in his very poor outline figure of Unio lepidus places it elsewhere, for if 

 there is any such thing as a characteristic in the panms group its radiation, when 

 present, is very remarkable and quite uniform. There is no doubt that Unio 

 trossnluit and Unio lepidus are synonyms. The paper of Mr. Simpson is to be com- 

 mended as marking a distinct advance in the study of the southern representatives 

 of this great family. It appeared in volume XV of the Proceedings of the United 

 States National Museum, 1892, and should be in the hands of every student of 

 Unio. 



The proofs of this article reached me when consultation of my library on one 

 or two points suggested by careful re-reading was impossible. The synonymy of 

 Unio parrus should have included the following: 



Unio singleyanus Marsh. Ephemerally described in the .Joliet Weekly, a 

 newspaper of Illinois, May, 1891. See also the "Nautilus," Vol. V, p. 29; Simp- 

 son, "Notes on Florida L'nionida," Proc. L^. S. Nat. Mus., Vol. XV, pp. 426, 

 427, pi. LXVIII, figs. 4, 5 (1892). Without doubt a synonym for Lea's Unio 

 marginis, itself a southeastern representative of Unio parrus. 



