814 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 
period, of the type, which is one of the highest among the true fishes. 
It probably belongs to the Percidw, although I have not ascertained the 
presence of teeth on the vomer, and there may be eight branchiostegal 
rays. As compared with the genera, recent and extinct, which are 
allied to Perca, it differs in the unarmed operculum and the preopercu- 
lum with teeth only on the lower limb, and in the presence of but two 
anal spines. It is therefore a weaker form than they, and, though of a 
higher type, less strongly protected by spines than the cotemporary 
Asineops. Mioplosus embraces the largest Physoclystous fishes yet 
known from this formation, and specimens are not rare at the. locality 
from which they have been procured. They are often in a state of ex. 
cellent preservation. The type of the genus is the Mf. labracoides. 
Char. spec.—The A. abbreviatus is represented by but one specimen, 
from which the muzzle has been broken away. It is the stout species of 
the genus, and the others succeed it in this enumeration in the order of 
their greater elongation of form. The depth at the first dorsal fin enters 
the total length (including caudal fin) three and a half times; and the 
depth at the first anal ray enters the length of the vertebral column 
two and eight-tenths times. Vertebre visible behind clavicle: D. 9; 
C.14. Radii: D.IX—I. 11; A. II—11; P.14. Ventral withavery weak 
spine. The last dorsal spines, as in all the other species, are very short, 
the anterior ones slender and moderately long; in this species, they are 
curved. The anal spines are short and slender, the first a rudiment. 
There are six rows of scales above and six below the vertebral column 
on the caudal peduncle. 
Measurements. 
Length of vertebral columiniessc05c<s5 ssn. oes necuuien wees deny chad cee etee sete 0.125 
Length of third dorsal spine ...-.. 2-22. 222 eee ee cee e eee jae eee cetmce eee eeisiee 0.025 
Length of ninth dorsal Spin@:isis 20s seicses siecw siswis s se Sus cows sues saewse ence nie 0.007 
Depth at:middle of first dorsal fi vase sons ses neice coe see vite weeeae vee ees ces 0.060 
Depth of catidal pedtnclenc< 0 sossa2 222 wets ioe aces ceed ese cee wceeonen eee 0.025 
MIOPLOSUS LABRACOIDES, sp. nov. 
This Perch is represented by five specimens, mostly in good preserva- 
tion. They have much the proportions of the Rock-fish. The origins of 
the pectoral and ventral are in nearly the same vertical line, and that 
of the first dorsal is not far behind them. ‘That of the first ray of the 
aual is below the second or third ray of the second dorsal. The rays of 
none of the fins are prolonged; the dorsal spines are slender and nearly 
straight, the longest (third), when depressed, reaches but four-tenths the 
distance to the first ray of the second dorsal. The last dorsal spine is 
very short. The soft dorsal rays are rather longer than the spinous. 
Formule :—Rays: D. IX—I.12; C.8—17—8; A. II—14; V.1.5. Verte- 
bre: D. 10; C. 15. 
The depth at the first dorsal fin enters the total four times; the depth | 
at the first anal ray enters the length of the vertebral column three times. 
