358 ADDENDA. 



2. S. irideus, Gibbons. Pacific Bkuok Tkout. Form 

 stout; head short, bluiitish; mouth small, the maxillary 

 scarcely reaching beyond eye. Streams W. of Sierra 

 Nevada. {S. 7iewberrii, Grd., /S. masoni^ Suckl.) 



cm. Scales small, in 165—205 rows. 



h. Caudal somewhat forked; head small, conical, rather 

 pointed. 



3. S. isuppitch, Rich. Black Trout of Lake Taiioe. 

 Rather slender; mouth moderate; opercle prolonged 

 backwards; scales in 180 rows. Streams W. of Sierra 

 Nevada. 



hh. Caudal double-ronnded ; head heavy, shortish, convex. 



4. S. spilurus, Cope. Big-Mouthed Trout. Mouth 

 very large, the maxillary reaching much beyond eye; 

 opercle not specially prolonged; black spots most numer- 

 ous posteriorly. Rocky Mountain region, Wyoming to 

 Arizona. 



YdiV. pleuriticus, Cope. Scales small, in 200 rows; 

 head carinate. Generally distributed. 



Var. spilurus, (Cope). Scales larger, in 170 rows; 

 he^d strongly convex. Utah to Colorado, etc. 



f Hyoid bone with an elongate band of small teeth (easily 

 scraped oil by careless oljservers). 



c. Head large and long — acuminate ; hyoid teeth weak ,• can- 

 dal somewhat forked. 



5. S. henshawi, G.& J. (sp.n.) Silver Trout of Lake 

 Tahoe. Head little carinate; body elongate, not much 

 compressed; scales in 160 — 184 rows. Streams of Cal. 



cc. Head comparatively short and blunt ; hyoid teeth rather 

 strong ; caudal less forked. 



G. S. stomias, Cope. Scales in 200 rows; head broad 

 and flat. LTpper Missouri. 



