32 G 
U. S. P. R. R. ESP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
quite extend as far as the vent. The pectorals are smaller than the ventrals, posteriorly 
rounded, and far from reaching the origin of the ventrals. 
Br. VIII: VIII; D 1, 10 + 1 ; A 1, 19 + 1 ; C 8,1, 9, 8, 1, 7 ; V 1, 8; P 1, 11. 
The scales are of moderate development, longer than deep, anteriorly snb-truncated, pos¬ 
teriorly rounded, exhibiting conspicuous concentric stria, but no radiating furrows. The 
lateral line is very conspicuous, linear, and nearer the back than the belly. 
The upper surface and sides of the head are greyish, whilst the dorsal region is greyish olive. 
Upon the upper portion of the flanks, along the course of the lateral line, exists a yellowish 
orange streak, dotted or rather speckled with black, the abdominal region being yellowish, 
unicolor, with a metallic reflect. The dorsal and caudal fins assume the tint of the back ; the 
anal, ventrals, and pectorals that of the helly. 
lleferences to the figures .—Plate LXXV, fig. 1, represents TJialeichthys stevensi, size of life. 
Fig. 2 is a dorsal scale. Fig. 3, a scale from the lateral line. Fig. 4, a scale from the abdo¬ 
minal region. 
List of specimens. 
Catal. 
No. 
No. of 
spec. 
Age. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
605 
i 
Adult. 
Puget’s Sound, W. T. 
1856 
Dr. Geo. Suckley. 
Alcoholic 
Dr. Geo. Suckley.... 
COREGONUS, Artedi. 
Gen. Char. —Body more or less elongated, sub-fusiform in profile. Head sub-conical; mouth rather small; snout truncated, 
sometimes quite protruding beyond the lower jaw ; both jaws always toothless. Teeth on the tongue. Branchial apertures 
continuous under the throat. Ventrals inserted posteriorly to the anterior margin of the dorsal fin, and situated opposite the 
adipose fin. Caudal fin furcated. Scales of moderate development. 
Syn.— Coregonus, Art. Gen. Pise. ed. IValbaumi, 1792, 53 ; &, Synon. Pise. 1793, 18.—Cuv. Regn. Anim. II, 1817, 162; 2d 
ed. II, 1829; &, ed. illustr. Poiss. 259.— Richards. Faun. Bor. Amer. Ill, 1836, 309. —DeKay, New Y. 
Faun. IV, 1842, 247.— Storer, Synops. 1846, 199.—Cuv. & Val. Hist. nat. Poiss. XXI, 1848, 454.— 
Agass. Lake Super. 1850, 336. 
In order that the value of the characters assigned to the genus Coregonus in the above 
diagnosis should be fully appreciated by our readers, it must be stated that we adopt the genus 
Argyrosomus of modern writers, characterized by a pointed snout and a prominent lower jaw, 
which projects beyond the upper one. The mouth in Argyrosomus being also more deeply cleft 
and the teeth on the tongue more conspicuously developed than in Coregonus , properly so called. 
Moreover, the premaxillar bones in Argyrosomus exhibit a row of small teeth, a character which 
leads to the genus Thymallus , a species of which inhabiting some of the fresh waters of the 
British possessions in Xorth America. 
COREGONUS WILLIAMSONI, Grd. 
Plate LXVI. 
Spec. Char. —Head contained five times and a half in the total length. Mouth small; posterior extremity of maxillar bono 
not extending quite as far as the anterior rim of the orbit. Eye moderate, sub-circular ; its diameter entering about five limes 
in the length of the side of the head. Anterior margin of dorsal fin nearer the posterior edge of the base of the adipose than 
