O NORTHERN ZOOLOGY. 



DESCRIPTION 

 Of the dried specimen. 



Form. — Profile elliptical, the ellipsis commencing acutely in the somewhat pointed 

 chin and conical head, but passing gradually into the thickish tail. The depth of the 

 body is greatest under the first dorsal, and appears to be about equal to the length of the 

 head, or one-third of the total length, excluding the caudal. Head flat above, covered with 

 scales as far as the posterior margin of the orbit : the forehead shows a slight median ridge 

 with a more prominent lateral one, and there are many fine streaks on the upper margin of 

 the orbit. The anterior sub-orbitar bone is marked by some short diverging ridges, and the 

 under and posterior margin of the orbit is more distinctly roughened by many small irregular 

 prominences. The orbit is circular, situated close to the forehead, and two of its own dia- 

 meters and a half above the articulation of the lower-jaw : it is also a diameter and a half 

 behind the extremity of the upper-jaw, and four diameters from the point of the suboperculum, 

 or most posterior part of the gill-cover. The mouth acquires a somewhat vertical aspect, from 

 the chin, or tip of the lower-jaw, projecting about a quarter of an inch beyond it, and from its 

 opening descending from the plane of the forehead at a considerable angle as it runs back- 

 wards ; the articulation of the lower-jaw is opposite to the posterior margin of the orbit. The 

 labials have a lengthened triangular form, the narrow apex only passing under the edge of the 

 sub-orbitar bone : the posterior dilated and truncated extremity projects considerably beyond the 

 tip of the intermaxillary, and extends farther back than the orbit : it is further widened by 

 the addition of a superior piece, or apophysis, whose corner is rounded. There are no pores 

 in the lower-jaw, but two circular openings of canals in the bone are visible through the dried 

 skin which covers them. 



Teeth. — The opposing surfaces of the intermaxillaries and lower-jaw are covered with 

 densely-crowded, curved, fine card-like teeth, or, as they ought perhaps to be called, in con- 

 formity with Cuvier's nomenclature, rather coarse " dents en velours'''' — the dental surface 

 being broad anteriorly, and narrowing to a point behind. The transverse, anterior, projecting 

 extremity of the vomer, and the outer edges of the palate-bones, are armed with finer teeth 

 " en velours," the dental surface of the latter narrowing to a point posteriorly like those of 

 the mandibles ; there is, however, a detached but contiguous patch just beyond this point on 

 the edge of the palate. The whole vault of the palate is smooth. The tongue, as we have 

 already mentioned, has been removed, and if Mr. Todd's account of the pharyngeal teeth be 

 correct, they are not distributed into the same number of patches as in the perch. 



Gill-covers. — Preoperculum having a narrow upright limb, covered with smooth skin, 

 there being a single small scale only, just above its angle : the lower limb is wider, and has 

 three scales in a single row, which does not cover half its surface : the whole edge of the 

 bone is smooth and even, with the exception of a very shallow wide notch at the base of the 

 upper limb. The interoperculum is comparatively broad, its depth exceeding that of either 

 the preoperculum or suboperculum ; it is covered by a row of ten scales, which leave its 

 under border naked. The bony operculum has au acute, oblique notch in its posterior 



