Occasional Papers of the Museum of Zoology 3 



simply followed the common custom of his time which per- 

 mitted the author of a new genus to rename all the species of 

 earlier authors that he included in his new group. 



It follows that Calceola Sw. is exactly the same group as 

 that subsequently described by Simpson as Pressodonta and 

 has priority over it. 



Ill 



In 1/93 Spengler, who was a leading Swedish concholo- 

 gist of that time, described in the Skrivter af Naturhistorie- 

 Selkskabet, III, p. 55, a supposed new species of Unio from 

 "North America" as Unio violaccus in the following words: 



"Testa crassa, oblonga, anticc liinc angnlosc flcxa, interne 

 violacea." 



This description described nothing and might apply to any 

 one of a very considerable number of North American species. 

 But Lea in his Synopsis referred it to Unio coniplanatns and 

 in this was doubtfully followed by Simpson. 



In 1913, Haas (Kobenhavn Nath. Aledd. 65, pp. 51-66) 

 published a paper on Spengler's Unios and figured the type of 

 his Unio violaceus, from which it would appear to be an ab- 

 normal specimen of the well known Unio complanatus. The 

 question is whether Spengler's name, his type having in 1913 

 for the first time been adequately described and figured, 

 should be given preference over the definite description of 

 Dillwyn in 18 17. 



The conditions of a valid specific description are explicitly 

 defined by the Code and have been further construed by 

 Opinion I of the International Committee, in which it is held 

 that the "indication" required by the rule does not include 

 museum specimens. Dr. Pilsbry has aptly stated the proper 

 construction of the requirements of the Code in another con- 

 nection (Pr. A. N. S. P., 191 5, p. 549) and substantially as 



