302 



NORTHERN ZOOLOGY. 



of the same distance. The profile curves moderately from the snout to the dorsal, just before 

 which the depth of the body is greatest, but it continues to be considerable at the insertion of 

 the anal, the belly running as it were into an acute edge at that place : the short piece of the 

 tail behind the anal is narrow. The head, forming exactly one-fourth of the length of 

 fish, excluding the caudal, has a conical profile when the mouth is shut, the apex being formed 

 by the tip of the lower jaw, which projects a very little beyond the commissure of the mouth. 

 The top of the head is comparatively broad and rounded, it's thickness at the nape being equal 

 to that of any part of the body, and the snout, when vieAved from above, appearing obtuse. 

 Eyes large, much nearer to the snout than to the gill-opening. Nostrils near the eyes. 

 Mouth toothless, small, its commissure descending obliquely and not reaching farther back 

 than the nostrils : the lower jaw, when depressed, projects considerably beyond the upper one. 

 Gill-covers. — Bony operculum quadrangular, its slightly-convex under edge being equal to 

 the anterior one, and fully one-third longer than the upper or posterior one : the latter is 

 widely emarginated, or cut with a concave curve. The suboperculum, one-third of the height 

 of the operculum, is rounded off posteriorly in the segment of a circle, forming an obtuse tip 

 to the gill-cover : both these bones are edged with membrane. Preoperculum narrow. 



Scales thin and sub-orbicular, their transverse diameter being rather greater than their 

 longitudinal one. A few crenatures may be obscurely seen on their basal edges with a lens, 

 and very faint lines proceeding from them towards the centre. There are about fifty-seven 

 scales on the lateral line, and the greatest diameter of one taken from the anterior part of the 

 sides measures a line and a half. A linear inch includes sixteen or seventeen of them in situ. 

 The lateral line is curved convexly downwards, just before the ventrals, rising so as to run 

 straight through the tail. It is formed by a short tube on each scale. 



Fins.— Br. 3—3 ; P. 17 ; D. 11 ; V. 9; A. 19 to 22 ; C. 19f 



The ventrals are attached a little anterior to the middle, between the tip of the snout and 

 base of the caudal, or opposite to the eighth ray of the dorsal ; their tips reach to the anal. 

 The anal and dorsal are high anteriorly, and become considerably lower posteriorly, with a 

 slight concave sweep ; the articulations of the first ray of each are obsolete. 



The air-bladder is divided by a contraction into two portions, of which the lower one is the 

 largest. There are forty vertebrae in the spine. 



Dimensions. 



Inches. 



Length from tip of snout to end of caudal lobes 5 



end of central caudal rays 



base of ditto . 



end of anal 



end of doisal . > 



beginning of anal 



anus 



beginning of dorsal 



ventrals 



tip of gill-cover . 



nape 



posterior edge of orb;t 



anterior ditto . 



nostrils 



tip of labials 



Lines. 



9* 



0* 



7 







2i 

 11 

 10| 



64 



1 

 1 



9 

 61 



tj 



*" :! 



3| 



Length of lower jaw 

 ,, pectorals 



„ ventrals . 



„ attachment of anal 



Height of anal anteriorly 

 „ posteriorly 



„ dorsal anteriorly 



„ posteriorly . 



Length of attachment of dorsal 

 ,, lobes of caudal 



„ its longest rays 



,, its central ditto 



Depth of caudal fork 



„ body at ventrals 



Thickness of body where greatest 



Inches. 



Lines. 







4 a 







1U 







si 



1 



H 







9 







24 







10^ 







3* 







8 



1 



3J 



1 



2 







4* 







H 



1 



■3-5 







6 



