818 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 
The greatest depth enters the total length 2.6 times; the length of 
the head enters the same 3.3 times. The spines are more robust, and 
the serrature of the preopercle more produced in the individual now de- 
scribed than in any of those of the P. serrata in my possession. The 
size is about the same as that of the latter species. 
PRISCACARA LIOPS, sp. nov. 
A smaller fish than either of the preceding is referred to this genus, . 
although it differs in one feature, regarded as important among the 
Pomacentride, i. e., the preopercular border is entire. It conforms closely 
to the P. serrata in other ‘respects, as the form of the dorsal fin, three 
anal spines, form ‘of caudal fin, character of scales and lateral line; 
edentulous jaws, and, indeed, in form to such an extent as to lead me to” 
suspect that in this genus, as in Lepomis, etc., the serration of the pre- 
opercle is not of much systematic value. One character by which the P. 
liops may be distinguished from P. serrata, in addition to the smooth 
preoperculum and small size, is the constantly larger number of rays in 
the second dorsal fin. , 
Formule :—Rays: D. X—13-14; C.5—19—6; A.III. 10-11. Verte- 
bre: D.9; C.13. The form is characterized by the downward production 
of the muzzle, or a descending slope of the front. One specimen does not 
present this character, perhaps on account of distortion. The pectorals 
originate below the first dorsal spine, and the ventrals a little behind 
it. The spines are moderately stout, and the emargination of tbe dor- 
sal fin is not deep. There are twenty-five rows of ctenoid scales trav- 
ersed by a vertical line from the middle of the spinous dorsal, and 
smaller scales cover the operculum and more or less of the preopercu- 
lum. 
Measurements. 
Total len stly sc. cuwsweseivwseuceactacedegjes cep tes een need hoke ddas ceebecediensc eds 0.113 
Length. of WeaQiccoss css ssretiscme soseus a cheateneaed caneieeecseudasadee cena 0082 
Length to first dorsal spine .--... .. 22-2 2-22 eee cee cee ee eee cece ee eee ee eee 0.034 
Length to first dorsal soft ray .. 2.2... .ce0 ceee cece cee cece cee cee teens eee 0.057. 
Length: to first anal spine... cc csswvavciwe meleeed docace setebesccdae cetedeesenns 0.057 
Length to base of caudal... 2-2-2. 2.2 eee eee ee eee eee eee Gace seat ase 0.086 
Depth at orbit... .1-. 22.2 ...00-02-2-- oon db eteeis ee has ieee eeenatncas 0.030 
Depth at first dorsal spine ....-... Avie <oaiach acne tse ae ee see oat Saeces 0.043 
Depth at first doraal soft ray ...--2. 22.02. eee ee cee ee cee ee eee eee cee eee 0.035 
, Depthiof caudal peduncle... 22 jccnsnevceiwesis nae aaa vemnecctaied decease ese 0.014 
Five specimens of this fish have been received. . 
GENERAL OBSERVATIONS. 
The species of this locality are distributed as follows, in their respect- 
ive genera. <A corresponding list of all the species known from the 
Green River Shale is also given :— 
