8o BULLETIN OF THE BUREAU OF FISHERIES. 



It seems probable that the relationships of S. regalis and also of 5. smaragdus, a representative 

 species found in Pyramid Lake, are with S. irideus of the western slopes of the Sierras, 5. smaragdus 

 having apparently departed farther from the parent form than has S. regalis. 



Salmo smaragdus, new species. Emerald trout. 



The trout here described for the first time is a native of Pyramid and Winnemucca Lakes and does 

 not seem to occur elsewhere. It is apparently a representative of S. regalis of Lake Tahoe, and in com- 

 mon with that form it is characterized by its peculiar color, remarkably different from that of other 

 species of the region. The upper parts of the head and body are deep emerald green, with a few small, 

 evanescent, dark spots scattered here and there, the sides of polished silver, and the ventral surface 

 dead white. The body is long and slender, the head rather short and rounded, eyes large, maxillary 

 weak, basibranchials without teeth, gillrakers few, slender and sharp, the scales large and very loosely 

 attached, and the fins thin and pointed, the entire appearance of the fish suggesting the depths of the 

 lake as its habitat rather than the river or the mountain torrent. From S. regalis this species differs 

 in being green above instead of blue, in having larger scales (there being 124 lateral series — 144 to 153 

 in 5. regalis), a more slender body, longer and more pointed snout, and a gill cover distinctly different 

 in shape, the upper or opercular part presenting a rounded, broad shoulder, while the posterior margin 

 is relatively truncate. 



The species is recognized by the older Piute Indians. To them it is the trout, "A-gaih, " in contra- 

 distinction to " Tomoo-agaih " or the winter trout, the large migrantsof S. henshawi which appear in the 

 lower Truckee River early in winter, and the " Tama-agaih " or spring trout ("tommy"of the anglers), 

 a smaller fish, also S. henshawi, though of a later run. It is also familiar to the more experienced fisher- 

 men of Pyramid and Winnemucca Lakes, who call it the "green-back."" By them it is distinguished 

 by its more slender form, the brilliant silver of the sides, the unparalleled green of the dorsal surface, 

 the frail, broad, thin scales which adhere to the fingers like bits of foil, the firm, deep-red flesh, and also 

 by the imusually strong and characteristic fight which ensues after the fish has been hooked. Their 

 description of this trout led indirectly to the discovery of S. regalis in Lake Tahoe. It is said by all 

 to be extremely rare, so that the most persistent fisherman sees but one or two during a season. It may 

 possibly escape notice in the hands of some anglers where it is confused with small, silvery examples 

 of the more common cutthroat trout, although even the less observant will immediately recognize the 

 difference when attention is called to the specific characters. But whether or not the species is rare, 

 the fact remains that while in the past countless numbers of large trout have been shipped from the 

 lakes, many even reaching the markets of San Francisco, this form with its strongly marked external 

 characters, and very desirable food qualities, has escaped the notice of natiu-alists and the serious atten- 

 tion of anglers and others interested in fishes. 



Description of type no. 75596, United States National Museum, a specimen measuring 480 mm. 

 in length, from Pyramid Lake, Nev., May 22, 1913. Sex, male. (See fig. 9.) 



Head 4. 5 in length to base of caudal ; depth 5 : depth caudal peduncle 10.5; snout 3 .8 in head ; vertical 

 diameter of eye 5.6; length maxillary 1.9; dorsal rays 11; anal 11; scales in lateral series 124; above 

 lateral line 26; between lateral line and base of ventral 23; between occiput and dorsal about 70. 



Body slender, the head and snout elongate when compared with 5. regalis. Maxillary comparatively 

 broad, rather thin and weak, not extending far beyond orbit. Gill cover obtusely roimded behind; 

 the opercle wide and with the upper edge broadly rounded, imparting to the gill cover a pronoimced 

 and characteristic shoulder. Branchiostegals 11. Gillrakers 9-1 1, long and acutely pointed. Vomerine 

 teeth in 2 distinct rows, the toothed area somewhat longer than in S. henshawi. Strong teeth on anterior 

 part of tongue; none on basibranchials; edge of maxillary except extreme posterior part with teeth. 



Scales notably large and loosely embedded; those immediately behind occiput and on ventral sur- 

 face minute. Fins naked. Lateral line with 123 pores, slightly decurved beyond its origin, and then 

 straight to middle of caudal. 



Longest (first) dorsal rays contained 1.8 times in head; pectoral 1.6; pectorals and ventrals acutely 

 pointed; ventral inserted on a vertical through base of third dorsal ray. Caudal deeply forked, the 

 lobes pointed. Adipose fin small and rather narrow. 



"The name "green-back "is not available, as it has been applied elsewhere as a common name for a particular trout, there- 

 fore "emerald trout" is suggested as an appropriate substitute. 



