242 
U. S. P. R. R EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
2. LAVINIA HABENGUS, Grd. 
« 
Spec. Char. —Body compressed, subfusiform in profile, and gradually tapering towards the peduncle of the tail. Head 
constituting the sixth of the total length ; diameter of the eye entering about five times in the length of the side of the head. 
Mouth moderate ; posterior extremity of maxillar bone, nearly even with a vertical line drawn before the orbit. Anterior 
margin of dorsal fin nearer the base of the caudal than the extremity of the snout. Insertion of ventrals nearly equidistant 
between the extremity of the snout and the base of the caudal fin. Caudal moderately furcated. 
Syn —Lavinia liarengus, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 184. 
This species is intermediate between L. exilicauda and L. alutacea. The most characteristic 
feature consists in the general shape of the body and the relative position of the dorsal and anal 
fins, which are wider apart. The size of these fins being nearly the same, and if any appreciable 
difference be observable, the anal would be found somewhat larger than the dorsal. The 
number of the rays in the various fins is as follow : 
D 1,10 ; A 2, 10 ; C 9, 1, 9, 8, 1, 8 ; Y 1, 10 ; P 16. 
The dorsal and anal are the only fins presenting differences of some specific value. The 
specimens before us are in a mutilated condition, inasmuch as the scales are all fallen. The 
dorsal region seems to have been of a much deeper hue than the lower half of the sides, which 
are whitish, as well as the belly, contrasting with the rather dark hue of the dorsal region. 
List of specimens. 
Catal. 
No. 
Cor. No. 
of 
No. of 
spec. 
Age. 
Locality. 
When col¬ 
lected. 
Whence obtained. 
Nature of 
specimen. 
Collected by— 
210 
2767 
i 
Adult. 
Monterey Plains, Cal. 
1854 
A. S. Taylor, Esq. 
Alcoholic. 
A. S. Taylor, Esq..... 
TRIBE OF POGONICHTHI. 
This fourth group is less uniform, if the teeth are taken into account. The latter belong to 
the hooked types, with or without grinding surface ( Dentes uncinato-submolares and uncinato- 
siibconici ), of the raptatorial (. Dentes raptatori ) and prehensile ( D. prehensiles ) kinds chiefly ; in 
most cases disposed upon a double series. But all its representatives are provided with buccal 
or maxillar barbels ; and the upper jaw, in projecting more or less beyond the lower, gives the 
mouth an inferior position, although not so decided as in the group of Catostomi, except in some 
species of the genus Argyreus, in which the snout is rather elongated and conical, and which 
suggested the name of lihinichtliys. In the species from the Pacific range, a thin cartilaginous 
pellicle is observed upon the jaws : illustrating what has already been stated, that the cartilagi¬ 
nous lips are not sufficient to characterize the group of Chondrostomi. Of course, it is in the 
latter where that character assumes its greatest development. 
This group or tribe was distinguished for the first time, without any name being affixed to it, 
in the “Proc. of the Acad, of Nat. Sc. of Philad. VIII, 1856, 184.” 
