32 ACANTHOPTERYGII. 
portion being usually considerably shorter than the posterior soft-rayed one; (2) the 
presence of only one or two anal spines; and (3) the toothless palate. 
One permanently fluviatile species (Haploitdonotus grunniens) is found in the rivers 
of Mexico and Central America, but whether any of the Scienid shore-fishes of this 
region ascend rivers above the influence of the tides is uncertain *. 
HAPLOIDONOTUS, Rafin., 1819. 
Aplodinotus, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1898, p. 1484. 
Body rather deep, compressed. Mouth subterminal; no barbels; premaxillaries protractile; maxillary 
concealed by the prexorbital; no supramaxillary; jaws with bands of small pointed teeth; palate 
toothless ; lower pharyngeals large, completely united, with molariform teeth; preoperculum weakly 
denticulated. Scales of moderate size, ciliated; lateral line curved anteriorly, continued nearly to the 
end of the caudal fin. A single dorsal, scaly at the base, with X 29-32 rays; anal with II 7 rays; 
caudal doubly truncate ; pectoral asymmetrical, pointed; ventrals each of a spine and 5 branched rays, 
inserted a little behind the base of the pectorals, without scaly axillary processes. 
1. Haploidonotus grunniens, Rafin., 1819. 
Corvina oscula, Giinth. Cat. Fish. i. p. 297 (1860). 
Aplodinotus grunniens, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1898, p. 1484. 
Depth of body 22 to 24 in the length, length of head 33 to 33. Back elevated, the ventral profile being nearly 
straight. Snout short, obtuse ; maxillary extending to below posterior part of eye, the diameter of which 
is about 5 in the length of head and 14 in the interorbital width. Scales 56-62 =. Dorsal X 29-82 ; 
spines moderately strong, the third highest, 3 the length of head and nearly as long as the longest 
branched rays. Anal II 7; second spine strong, about as long as the longest dorsal spine, shorter than 
the anterior branched rays. Pectoral as long as the head. Silvery, back darker; vertical fins dusky. 
Hab. Rivers and lakes of North America, from the Great Lakes to Chiapas (in Mexico 
recorded from Matamoros in Tamaulipas and the Rio Usumacinta). 
This species, here described from Winnipeg examples of from 250 to 300 mm., 
attains a weight of 50 or 60 pounds. 
Fam. 7. PERCIDA. - 
The Percide are a large family inhabiting the fresh waters of North America and 
Western Eurasia. The majority of the American species are the small fishes known 
as “darters,” a few of which occur in Northern Mexico. These belong to two very 
closely allied genera, Percina and Etheostoma, which may be distinguished from other 
Perciform fishes by the following diagnosis :— 
Body more or less elongate and compressed. Mouth small or moderate ; pramaxillaries not protractile, except 
at the sides ; maxillary exposed, but slipping under the preorbital for the whole length of its upper edge ; 
villiform teeth in the jaws and usually on the palate. Scales small, denticulated. Two dorsals, with 
* In the British Museum are examples of Bairdiella icistia, Jord. & Gilb., and Cynoscion xanthulus, Jord. & 
Gilb., collected by Herr Forrer in the Rio Presidio, but probably near the mouth of the river. 
