70 



BUI.I.ETIN OF THE BUREAU OF FISHERIES. 

 Measurements of Coregonus williamsoni. 



Length of body mm 



Length head 



Depth body 



Depth caudal peduncle 



Length caudal peduncle 



Length snout 



Length maxillary 



Diameter eye 



Interorbital width 



Depth head 



Snout to occiput 



Snout to dorsal 



Snout to ventral 



Length base of dorsal 



I^gth basex)f anal 



Height dorsal 



Height anal 



Length pectoral 



Length ventral 



Length caudal 



Dorsal rays 



Anal rays 



Scales lateral series 



Scales above lateral line 



Scales below lateral line 



Scales before dorsal 



I,ake Tahoe. 



338 



9 



0.19s 



.18 



.06 



.14 

 .06 



•OSS 



■OS 



• 065 



•^35 



.16 



•335 



•S3 



•I2S 



.105 

 •135 

 . II 

 •IS 



•I2S 

 .165 



9 



o- 205 

 • 20 

 .06s 



•135 



.065 



•05S 



•OS 



.065 



•IS 



•17 



•4SS 



•S3S 



. 12 



. 10 



.125 



. 11 



■155 



■13 



■17 



12 

 II 

 89 

 9 



.195 



.06 



.14 



.065 



.06 



.05 



.06 



.14 



■17 



.46 



•55 



.165 



.13 



•17 



187 



9 



O. 22 

 .20 

 .06 



.145 



.065 



.06 



•05 



.06 



•<S 



• iS 



• 46 

 •55 

 .105 



• 10 

 ■14 



• los 

 •175 

 •13 



185 



S 



o. 215 



•195 



• 065 

 .14 

 .06 

 •055 

 •OSS 

 .06 

 .145 

 .18 

 .46 

 •SSS 



• II 



. 10 



• 13 



. II 



.16 



■135 



Fallen Leaf Creek. 



o. 23 

 • 20 

 .065 

 .14 

 .065 

 .065 

 .06 

 .065 



.IS 

 .iS 

 •4S 

 ■51 



o. 21 



.18 



.06 



•IS 



.07 



.065 



.06 



.06 



.14 



.17' 



•445 



•SI 



• 12 



.105 



.13 



. II 



.16 



.13 



.205 



89 



o. 22 

 •19 



.065 



.16 



.07 



.065 



.065 



.06 



.14 



•17 



•43 



•SO 



•135 

 • 105 

 •IS 



o. 23 

 ■17 

 .06 

 .IS 

 .065 

 . 065 

 .06 

 .07 

 ■145 

 .18 

 •44 

 •SI 



• 13 

 •IIS 

 •IS 



. 12 



• 17 



• 14 



.215 



0.23 

 • 19 

 .06 

 .15 

 .06 



.065 



.065 



.065 



.15 



.185 



•44S 



•51 



■13 



. II 



•13 



. II 



•175 



. 12 



o. 24 



• 17 

 .o5 

 .14 

 .07 

 •07 



• 07 

 .065 

 ■>4S 

 •19 

 •445 

 •S3 

 .125 

 . II 

 .125 

 . 12 



• 17 

 . 12 



Salmo henshawi Gill and Jordan. Tahoe trout. 



This trout is best known to ichthyologists and anglers from fish caught in Lake Tahoe, in its numer- 

 ous tributary streams and small lakes, and in the upper portions of the Truckee River. Here its most 

 striking characteristic is the dark-olive body with an array of large black spots scattered almost uni- 

 formly over the entire surface. The species is distributed tliroughout the entire Lahontan system, 

 however, and living under greatly diversified conditions it seemingly reacts to its surroundings, appear- 

 ing in a medley of variations of color, such as are not often observed among individuals of a single 

 species. 



Examples in bright nuptial dress may be seen in Lake Tahoe in May and early June. The males 

 are then of a dark yellowish-olive color, with faint metallic reflections, the dark color being uniform 

 from the back to the ventral surface. On tlie side is a broad, pinkish stripe, indefinite in outline, but 

 about 10 scales wide and located mostly below the lateral line, originating at the opercle and extending 

 to below the adipose fin, beyond which it gradually fades out and disappears. Each scale included 

 in this stripe and also in a broad area above and below is narrowly edged with pale yellow. The 

 opercle, preopercle, subopercle, and a triangular spot above the axil of pectoral are scarlet or yel- 

 lowish scarlet. The under surface of the lower jaw has two parallel stripes of bright red, the color not 

 extending on the mandibular side of the membranes. There is a patch of bright red on the tongue 

 beneath the tip. The inner edge of the shoulder girdle is bright red. One or more small orange spots 

 may often be found on the head, especially on the cheeks and jaws. The entire head and body, 

 togetlier with the impaired fins, are marked with dense, brownish -black spots, usually larger than the 

 pupil, and rounded oval in outline, widely spaced and fairly regular in distribution. On the dorsal fin 

 the spots are arranged in five pretty well defined rows, parallel with the outline of the back. The 

 adipose fin bears two or three spots; they are numerous on tlie caudal, but not more than six or seven 

 occur on the anal, usually at the base. Females are similarly colored, though much lighter and with 

 more metallic luster. 



Males often vary toward lighter tints, while some females are occasionally darker than the others, 

 sometimes rendering the determination of sex on color alone very difficult. Frequently a very light- 

 colored, silvery specimen of either sex appears. Such fishes are distinguished by the bright metallic 

 luster of the sides and also by having smaller and more elongate spots. These are known as silver trout. 



