
656 The American Naturalist. [July, 
OLIGOPLARCHUS SQUAMIPINNIS, gen. et. sp. nov. Percidarum.— 
Apparently allied to Lepomis, but I cannot determine the presence of 
vomerine teeth or the number of the branchiostegal rays. 
Char. gen.—Jaws with a few rows of conic acute teeth. Apparently 
no palatine or pterygoid teeth. Operculum without notch or produc- 
tion of the posterior angle or border. Bones of the head smooth, and 
not serrate. Scales ctenoid, with rough area externally and concentric 
grooves internally, and radii proximally. Spinous radii, D. X. ; A. III. ; 
P. I. Spinous dorsal continuous with soft portion, both together 
much larger than the anal fin. Caudal fin furcate. Skull with a 
median crest, from which a series of interneural bones extends to those 
supporting the dorsal fin. Lateral line not discoverable. 
This genus appears to be allied to the Percid genera related to Cen- 
trarchus, which now inhabit North American waters. It differs from 
all of them in one way or another, as for instance in the form of the 
opercular border, or in the number of the spinous rays and their pro- 
portions. It is perhaps most closely allied to the extinct genus Plio- 
plarchus Cope, differing mainly in the small number of anal rays; 
that genus possessing from five to seven. These differences are the 
same as those that separate some of the recent genera, showing that 
the same diversities existed in Cenozoic times as now. In the best 
preserved specimen I count six branchiostegal rays, but I am not sure 
that this is the entire number. The pubes are connected with the 
clavicles directly ; vertebrze with lateral fossæ. 
Char. specif.—This species is the most abundant, as many as twelve 
individuals having come under my observation. The largest is about 
equal in size to our smaller existing sunfish, Lepomis pallidus. Radii, 
D. X 9-10; C. 5, 17, 5; A. III 7-8; Vi-s; P.Ir2. The dorsal 
spines increase regularly in length to the tenth ; the first rises above the 
base of the ventral fin, which is a little behind the base of the pectoral. 
The anal fin commences below the first soft ray of the dorsal fin, and 
is nearly coterminal with the last soft ray of the same. The ventral 
spine is quite as robust as any of the dorsal spines, and is subquadran- 
gular, with the external and posterior faces convex, and the ‘anterior 
grooved. The anal spines are robust, the third the longest. The 
scales are in from twelve to fourteen longitudinal rows. In one speci- 
men, of larger size than the others, there are seventeen rows. This 
probably indicates another species, but it is too imperfect for charac- 
terization. Scales rather smaller than those of the body extend on the 
interspinous membranes of the soft dorsal and caudal fins, and on the 
opercular and suborbital regions of the head. Vertebre, D. 12, C. 
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