128 



PROCEEDINGS OF THE ACADEMY OP 



ichthyologist. On another accasion, I will give my reasons for the retention 

 of this family near the Acanthopteri and against the supposed affinity of its 

 members to either the Salmonoids to which Valenciennes has referred them, 

 or the Silnroids, to which Giinther has lately approximated them. 



The species herein described, as well as the Alepisaurns altivel s of Poey, or 

 those Alepidosauroids, whose ventrals have each a spine and twelve branched 

 rays, may at least be placed in a separate subgenus, to which the name of 

 Caulopus may be given. The number of ventral rays appear to be constant, 

 and as there is rarely so wide an interval as that of between nine and thirteen 

 in the same natural genus, its title to such distinction or even generic rank 

 appears to be good. 



Alepidosaukus (Caulopus) bokealis Gill. 



The head has the form and outlines common to the other members of the 

 tribe. The superior surface is flat and declines in a nearly uniform line to the 

 snout, and is sculptured as usual. The height at the vertical of the preoper- 

 cular margin enters nearly four times and a half (44-100) in the length ; the 

 width at the same region nearly equals a fourth (24-100) of the same ; thence 

 it regularly diminishes to the pointed snout. 



The eyes are circular and normally large, a diameter entering eighteen- 

 hundredths (18-1001 times in the head's length. The distance of the eye 

 from the snout equals two-fifths (40-100) of the length. 



The nostrils are nearer to the eyes than to the snout, and are situated at 

 the twenty-third-hundredth (23-100) of the length. The operculum is of 

 a rhomboidal form ; above it is straight, and its length exceeds a quar- 

 ter of the head's ; its longest diameter, from the centre of radiation to the 

 postero-inferior angle margin, equals three-tenths of the same ; its posterior 

 margin is nearly vertical, or rather parallel with the preopevculum ; the ante- 

 rior curved upwards from the inferior. Its surface has about eighteen promi- 

 nent stria? or ridges, besides additional smaller ones. 



The coalescent inferior opercular bone is divided into two parts by an ele- 

 vated stria or ridge, commencing above the articulation of the lower jaw ; the 

 part above that ridge is vertically semi-kastlform, or irregularly triangular, with 

 an oblique emarginated base or posterior side ; from its angle of radia- 

 tion above the lower jaw, about nine stria? radiate ; its least diameter, from the 

 apex to the base or posterior oblique margin, equals an eleventh (9-100) of the 

 head's length ; its greatest, behind the preoperculum, exceeds twice the lat- 

 ter (19-100), while that of its posterior oblique side equals only about an 

 eighth (12-100) of the head. The inferior portion, besides the upper dividing 

 ridge, has one under it continued to the margin, and the whole surface has 

 coarse radiating stria? or ridges, the upper of which are interrupted behind by the 

 anterior of two or three ridges parallel with the posterior border. 



The lower jaw is robust, and its length is equal to three-fourths of the head's. 

 Its upper outline is slightly arched or convex. Its greatest height is under the 

 last median trenchant small teeth of the sides, where it equals an eighth of the 

 length of the head. 



The teeth of the intermaxillary bones are very small, acute and numerous, 

 and continued to the angle of the mouth. There are about three very large 

 and nearly equal vomerine teeth, which are slender and considerably curved. 

 The length of the hinder equals a seventh (15-100) of the head's length ; one 

 is unpaired, while the two behind are nearly opposite. 



The large palatine teeth are shaped like the vomerine and equal in length 

 nearly a tenth of the head's ; there are in our specimen one on the left and 

 two on the right side. The succeeding small trenchant teeth commence con- 

 siderably behind, the first being scarcely before the anterior border of the 

 orbit ; they are not contiguous, and rapidly increase in size, are scarcely cari- 

 nated, and the posterior border is slightly recurved. There are about six. The 



[March, 



