318 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



V:ir. sisco\V't (A-assi/.) J. it C*.Si*<-<nr<'t S.ilmnn. 



P.ody short and deep, covered with thick skin, there being an exces- 

 sive tendency to the development of fatty tissue. Head very short and 

 deep, its upper surface broad and short, covered by a skin so thick as 

 to completely hide the bones; no distinct median carina. Month very 

 large, its gape narrower than in S. iidinni/ciiuJt. Teeth weaker than in 

 N. luuiuiiiciixh ; supplemental bone also shorter and broader. Maxil- 

 lary a little more than half the length of the head. Caudal (in well 

 forked. Scales rather small, about 173 in the lateral line. Coloration 

 as in S. nntntnjcnxh^ but usually paler; lin-ra\s the same. Lake Supe- 

 rior; abundant, but not yet found elsewhere. Very close to the preced- 

 ing, but differing in the shortness and breadth of the bones of the head 

 and in the extreme fatness of the ilesh. It is probably a local variety 

 rather than a distinct species. 



(Salmo siacowi l Agassi/, Lake Superior, 1850, 333.) 



**Vomer without raised crest, the chevron only being toothed; red-spotted. (>'<//- 



ri'liinix. ) 

 flllyoid liono with a narrow median band of teeth (sometimes lost). 



51O. S. oqiiassa (Grd.) Gill & Jor.Oqiiawa Trout; lilue-back Trout. 



Body elongate, considerably compressed, less elevated than in the 

 other species of this genus, the dorsal outline regularly but not 

 strongly curved. Head quite small, much smaller than in any other 

 of our trout, its upper surface ilattish. Mouth quite small, the maxil- 

 lary short and moderately broad, scarcely extending to the posterior 

 margin of the eye. K\ e large, IU in head. .Jaw* about equal. Scales 

 small, those along the lateral line somewhat enlarged. Pectoral and 

 ventral fins not elongate; caudal tin well forked, more so than in the 

 other species. Preopercle as in X. funtliitillx, but the lower limb more 

 developed; operdes without concent ric stria-. Coloration dark blue, the 

 red spots small and round, much smaller than the pupil, usually confined 

 to the >ide> of the body ; sides with traces of < lark bars; lower tins varie 

 gated, as in N. /..iitintilix. Head ~>; depth .'. 1>. 10; A. 1). Lat. 1. 1>30; 

 gill rakers about 1',-f 11. L. 11' inches. Smallest and handsomest of our 

 trout, as \et known only from the Kangeley Lakes, in Western Maine. 



(,SV//,m/</"" vs " (; ii:"il. 1'ior. Ar:i,|. N:it. S.-i. I'hila. L8i 1,963: X<ihn<i o'/tutKHd Uiiiither, 

 \ i, l.'.l ; .Joi-daii. I'm. . I . B. Nai. Mils, i, si.) 



51 1. S. iKliesi (Ciiutli.-D I'.ran. 



(ireenish above, sides silvery or deep red, with very small red spots, 

 much smaller than the pupil; lower fins deep red, with the anterior 



