80 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



The Charrs, or Salvelijii, form a strongly marked group, which has 

 several times been distinguished as generically or subgenerically differ- 

 ent from the true Salmoiis. The absence of teeth on the shaft of the 

 vomer has been the character most usually relied on to distinguish the 

 Charrs. A more important character is, however, seen in the form of the 

 bone, which is boat-shaped, with the shaft short and depressed. The 

 Charrs are further distinguishable by the very small size of the scales,^ 

 and also by the coloration, they being always red-spotted, and with the 

 lower fins peculiarly colored. 



No one who examines the skull of the Charr can doubt its generic 

 distinctness from Salmo. The question of the nomenclature of the 

 genua is a matter perhaps of some uncertainty. The group has long 

 been known as Salvelini, but that name was hardly given by Nilsson 

 in the usual generic or subgeneric sense, but merely as a plural nouu 

 referring to an assemblage of species. 



In 1836, Richardson used the name Salvelinus for the •'subgenus'' of 

 Charrs. The use of the name in nomenclature therefore dates from 

 Richardson. 



In 1842, DeKay founded his genus Baione on the young of one of the 

 species of Charr [S. fontinalis)', Baione is therefore a synonyn> of Salve- 

 linuSj although giv^en under a different supposition. 



Somewhat later, tbe genus Umhla was proposed by Rapp for those 

 SalveUni which have teeth on the byoid bone. As Salmo salveliuus L., 

 the presumable type of SalveUnvs, has such teeth, Umhla probably is alsa 

 a mere synonym of Salvelimis. That the character of liyoid teeth is not 

 a generic one in this case is evident from the close relationship of such 

 species as S. oquassa and S.spectabilis, with hyoid teeth, with S. fonti- 

 nalis and S. bairdi, species destitute of such teeth. The teeth in S. spec- 

 tabilis and S. oquassa are too few and small for their absence or presence 

 to be a geueri<; character. In the subgenus Salai', the case is precisely 

 the same. 



In 1867, Dr. Giinther proposed a genus Hucho for the SalveUni with- 

 out hyoid teeth. The genus cannot stand on that basis, but neverthe- 

 less it appears to be valid, its type, Salmo hncho L. {Hucho germanorum 

 GUnther), being a Pike like fish, very unlike, both in lorm and habits, 

 the genuine species of Salvelimis. The single known species of Hncho 

 as thus restricted, inhabits the Danube. 



The remaining subdivision of the old genus Salmo, for which the 

 name Cristivomer has beeu proposed by Dr. Gill and myself, is peculiar 

 to the lakes of the northern part of America. 



The relations of Cristivomer are entirely with Salvelimis, a fact which 

 has not hitherto been noticed. Its vomer differs, however, from that of 

 Salvelimis in being provided with a raised crest tiush with the head or 

 chevron of the bone. This crest is posteriorly free from the vomer for 

 some distance, and is armed with a series of stout teeth. There is also 

 a strong band of hyoid teeth, the dentition generally being more com- 

 plete than in most other Salmons. 



