8 
U. S. P. R R. EXP. AND SURVEYS-ZOuLOGY-GENERAL RE PORT. 
AMBL< PL1TES, Rafin. 
Gen. Char. Body compressed; dorsal and ventral outlines sub-depressed. Head large. Math large also; lower jaw longest. 
Velvet-like teeth on the jaws, the vomer, palatines, and tongue. Cheeks and opercular apparatus scaly. Branchial apertures 
continuous under the throat. Spinous portion of dorsal fin lower than the soft, and extends upon a longer base. Anal fin 
provided with five or more spiny rays. Insertion of ventral fins a little behind the base of the pectorals. Caudal fin posteriorly 
sub-concave. Scales well developed, and generally ciliated posteriorly. 
Syn.— flmbloplites, Rafin. Icbth. Ohiens. 1820, 33.— Agass. Amer. Journ. of Sc. XVII, 1854, 299. 
This genus is very closely allied to the preceding one, from which it is to he distinguished hv 
the conformation of its dorsal fin. The latter is composed of a greater number of spiny rays, 
occupying a base of a greater extent than the soft and articulated rays. The spines themselves 
are lower than the soft rays, so that a kind of depression may be said to exist between the two 
portions of that fin. 
Two species are referred to this genus, A. ichtheloides and A. aeneus. Of the latter we give 
the following figure and description. 
1. AMBLOPLITES AENEUS, Agass. 
Rock Bass, Ate. 
Plate 1. 
Spec. Char. —Posterior extremity of maxillary extending to a vertical line intersecting the pupil. Insertion of ventrals oppo¬ 
site the base of the pectorals. Anterior spiny ray of anal fin under the ninth dorsal one. Posterior margin of caudal fin slightly 
emarginated. Upper regions of head and body of a coppery brown ; inferior regions, yellowish brown. 
Syn.— Cichla cenea, Lesu. Journ. Acad. Nat. Sc. I, 1822, 214, fig.— Ivirtl. Rep. Zool. Ohio, 168, 191. 
Centrarchus aeneus, Ccv. & Val. Hist. Nat. Poiss. Ill, 1829, 84.— Rich. Faun. Bor. Amer. Ill, 183G, 18. PI. Ixxv.— 
DeKay, New Y. Fauna, 1842, 27, PI. ii, fig. 4.— Kirtl. Bost. Jour. Nat. Hist. IV. 1842, 229. PI. xi, fig. 1. 
Storer, Synops. 1846, 37. 
Rock Bass, Goggle-eyed Bass, Black Sun Fish, Vernacular. 
The general aspect of this species is sub-elliptical when seen in profile ; the dorsal and 
abdominal outlines being sub-depressed. The greatest depth of the body is more than the third 
of the total length. The greatest thickness holds the same relations towards the depth as the 
latter holds towards the length. 
The head is very large, though constituting something less than the third of the total length. 
Its occipito-frontal declivity is gradual towards the snout, which assumes a wedge-shaped 
appearance upon the plate. The lower jaw is longest and protrudes slightly beyond the upper. 
The cleft of the mouth is large and obliquely directed upwards. The posterior extremity of the 
maxillary extends to a vertical line intersecting the pupil. 
The tongue is very large and fleshy, bearing a sub-elliptical patch of velvet-like teeth almost 
as conspicuous as those situated upon the palatine bones, the front of the vomer, and upon the 
jaws. The eye is large and circular ; its diameter entering nearly four times and a half in the 
length of the side of the head. The anterior nostril is equidistant between the anterior rim of 
the orbit and the margin of the upper jaw ; the posterior nostril is equal in development with 
the former and lies between it and the orbit. The external margin of the opercular bones is 
without spines or serratures of any kind ; the opercle, sub-opercle, and inter-opercle are covered 
with scales considerably larger than those which may be observed on the cheeks. The branchial 
apertures are continuous under the throat; there are six branchial rays. 
