PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 71 



The species of OnroiIn/itcJiKs iU [)resont aduiittcd by Dr. Gill niul 

 myself may bo biietiy (ompaicd as follows: — 



n. Body more elongate, hoaviLH' ibiward ami less compressed than in the next; jaws 

 iu the adult males very unequal : the lower jaw prolonged and hooked 

 upwards; the upper jaw sMll more elongate and curled over the tip of the 

 lower, the profile of the forehead being concave when viewed from the side: 

 teeth of the premaxillarios and of the tip of the lower jaw greatly enlarged 

 and hooked (Subgenus Oncorhynchus.) 



b. Scales very small, iu more than 200 transverse rows; smaller on caudal peduncle 

 than on flanks ; form much distorted in the adult males, the fleshy hump at the 

 shoulders being greatly developed, and the caudal peduncle slender and rather 

 elongate; the jaws greatly prolonged and curved ; size small. (Pacific coast 

 and streams, Washington to Kamtschatka.) ■' ORBUSCnA.* 



bb. Scales medium, in about 170 (15.") to 180) transverse rocrs; form distorted, but 

 less so than in the ])receding, the fleshy hump considerably developed in the 

 males, and the jaws greatly elongated and liooked ; branchiostegals about 16. 

 (Pacific coast and streams, Oregon to Kamtschatka.) iCKTA.t 



bbb. Scales large fin- the genus, in about 133 transverse rows. 

 c. Form elongate, not greatly compressed, the greatest depth iu advance of the 

 middle of the body; the males with the caudal peduncle rather slender, and 

 with a well-marked fleshy hump, and with the jaws much elongated and dis- 

 torted ; caudal flu feebly forked ; branchiostegals about !:>. (Pacific coast 



and streams, California to Kamtschatka.) NEiiKA.t 



cc. Body elongate, compressed, the greatest depth (iu female and immature speci- 

 mens at least) being just under the dorsal fin ; depth of body one-fourth of 

 length, or a little more ; head moderate, rather bluntly pointed ; less distorted 

 in male specimens than in the preceding species; maxillary shortish, curved, 

 reaching somewhat beyond eye; caudal flu more or less forked ; brauchioste- 



gals 15 or IG. (Coast and sti'eams, California to Alaska ) quixxat. 



aa. Bodj" oblong, very strongly compressed, the dorsal region much elevated ; a nearly 

 even slope from the snout to the base of the dorsal flu ; dorsal flu unusually 

 far back, the first ray being behind the middle of the body ; head long, deep, 

 compressed, but still wide ; mouth extremely large and very oblique ; the jaws 

 about equal in the females ; in the males, the lower jaw protruding beyond the 

 upper, which is curled up like the snout of a snarling dog, showing the 

 enlarged canines, the premaxillaries never booking over the lower jaw, as is 

 the case with Oncorhynchus proper; dentition as in typical Oncorhynchus. 



(I^bgenus Hypsifario (iill.) 



*Oxcoi{nYxciiL's GORBUSCHA (Walb.) Gill & Jordan. — Gorhuscha, Pennant, Arctic 

 Zoology. — Sahno (jorbnscha, Vralbaum, Artedi Gen. 1792. — Sahnof/ibhtr, Bloch, Schneider, 

 Ichthyologia, IdOl. — Sahiu) proteus, Pallas, Zool. Rosso-Asiatica, l8l\.—Snhno (jibber, 

 Suckley, l-'lil. — Oncorhynchus yorbuscha, .lordau, Man. Vert. fd. 2d, 187 ■'. 



tOxcoHiiYXCiJUS KETA (Walbaum) G. & ,1. — Kchi vd 7.«///,o, Pennant, Arcti(- Zool- 

 ogy. — Sahno Ida vel kayko, Walliauui, 1792. — HuUno levin vel kaylo, l>loch, Schneider, 

 IBOl. — Sahno layoccphalun, Pallas, 1811. — SaJmo scvnlcri, Ricliardson, 1831). — Salmo conjlu- 

 entus, 1861. — Oncorhynchus keta, .lordan, M lU. Vert. k1. 2 I, 1878. 



tOxcoiuivxciiu.s XERKA (Walb.) Gill «fe ,}o\-.—NwrLa, Pennant, Arctic Zoology. — 

 Salmo ncrka, Walbaum, 1792. — Sahno lycaodon, Pallas, IBll. — Salmo japoncnsls, Pallas, 

 1811. — f Sahno paucidcns, Richardson, 183(.). — Sahno consuetus, Richardson, Voyage of the 

 Herald, 1854. — Sahno dermathuis, Richardson, /. c. 1854. — Sahno canis, Suckley, 1861. — 

 Salmo cooperi, Suckley, 18(51. — Sahno scoukri, Suckley, 18G1, (not of Rich.). — Salmo trun- 

 catus, Suckley, 1861. — f Sahno rkhardi, Suckley, 1861. — Oncorhynchus lycaodon, Giiuther, 

 1867. — Oncorhynchus ncrka, Jordan, 1878. 



