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BULLETIN OF THE BUREAU OF FISHERIES 
spine and 5 branched rays ; vertebrje more tlian 30 ; sides with a silvery longitudinal 
band. 
This is a large family of small fishes. Some of the members inhabit fresh 
water, but the majority of them live in salt and brackish water. 
10. Genus THYRINA Jordan and Culver 
Thyrina Jordan and Culver, Proc, Cal. Ac. Sci., 2 ser., V, 1895, 419 (type Thyrina evermanni Jordan and Culver). 
Melaniris Meek, Pub., Field Col. Mus., Zool. Ser., Ill, 1902, 117 (type Melaniris halsanas Meek). 
Body elongate, compressed; trunk sharply compressed ventrally; profile in 
advance of dorsal almost straight and nearly parallel with the posterior half of the 
ventral contour; lower jaw included; teeth unequal, the outer ones more or less 
enlarged in each jaw; scales often crcnate, particularly on the back; origin of 
first dorsal well behind the origin of anal; base of anal longer than head; pectoral 
fins rather long, frequently longer than head. 
A single species, which appears to be undescribed, was taken in fresh water. 
11. Thyrina guija sp. nov. 
Pepesca; Manjuda; Alfiler; Rovalete 
Type No. 87273, U.S.N.M.; length 88 mm.. Lake Guija, El Salvador. 
Head 4 to 4.75; depth 5.5 to 6.65; D. Ill to V-8 to 10; A. I, 22 to 26; scales 
43 to 47. 
Body very elongate, compressed; abdomen rather sharply compressed, almost 
but not quite forming a keel; caudal peduncle long and slender, at least twice as 
long as deep, its least depth 2.55 to 3.8 in head; head rather short, flat above; 
snout moderate, its length 2.9 to 3.2 in head; eye 2.9 to 3.5; interorbital 2.4 to 2.7; 
mouth small; the small hidden maxillary reaching nearly to anterior margin of eye; 
premaxillary fully protractile, the anterior margin strongly curved, posteriorly 
greatly extended; lower jaw included, a little shorter than the upper; teeth in jaws 
in bands, the outer series in each jaw enlarged, those of the upper jaw more so than 
in the lower jaw and placed on the extreme outer edge of the jaw, curved inward 
and exposed when the mouth is closed; gill rakers short, about 16 on lower limb of 
first arch; scales mostly with straight edges, those on back with rather broad 
indentations, small scales extending on base of dorsal but none on the other fins; 
origin of spinous dorsal over the base of about the sixth ray of the anal, the spines 
reaching less than half the way to origin of soft dorsal; origin of the soft dorsal over 
or a little behind middle of anal base and about half as far from base of caudal as 
the margin of opercle; caudal fin forked, the lower lobe larger and longer; anal fin 
long, its base extending slightly beyond the end of the base of second dorsal, origin 
of anal about equidistant from posterior half of eye and base of caudal; ventral fins 
small, inserted about equidistant from margin of opercle and base of caudal; pectoral 
fins longer than head, falcate, 3.45 to 4.25 in length of body; vertebrae 20 + 20. 
Color greenish above, silvery below; sides with a silvery lateral band, about 
the width of the pupil, with a dark margin above; the scales on the back with dusky 
punctulations; a dark vertebral line; upper surface of head dusky; fins mostly pale 
green to translucent; a dark line along base of anal. 
