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FISHES OF THE PHILIPPINES. 275 
Butis serrifrons is stated by Rutter to differ from Butis caperatus (Cantor) in having the mouth 
“nearly horizontal” (not ‘‘nearly vertical”), and in haying two (instead of one) serrated ridges in front 
of each eye. In the typegvhich we have examined the mouth cleft makes about 35 degrees with the 
horizontal. 
As there are two ridges in front of each eye, even in those species of Butis (butis, amboinensis, etc.), 
which lack the strongly serrated orbital crests, it is doubtful whether Cantor’s failure to describe more 
than one in Butis caperatus denotes the absence of the second. Cantor’s estimation of the angle of the 
gape as ‘“‘barely vertical” was evidently a comparative one, with reference to Butis butis. It may 
also easily have been influenced by the condition of the specimens. 
One specimen, 2 inches long, from Iloilo. 
The genus Prionobutis Bleeker is nominal, differing from Butis only in the more marked serration 
of the orbital crests. The species of Butis and Prionobutis agree in coloration, all having the black 
spot at base of pectoral, with the smaller white spots above and below. 
246. Butis butis (Hamilton-Buchanan). 
Cheilodipterus butis Wamilton-Buchanan, Fish. Ganges, 57, 367, 1822; Ganges. Gray & Hardwicke, Illus. Ind. Zool., 1, 
pl. 93, fig. 3. ; 
Eleotris humeralis Cuvier & Valenciennes, Hist. Nat. Poiss., x11, 246, 1837; Bengal. 
(?) Butis butis Bleeker, Revis. Eleotriformes, 64, 1875; Sumatra, Borneo, Amboina, Philippines, ete. 
Butis melanostigma Bleeker, Blenn. & Gob., 23, 1849; Maduras Straits. Bleeker, Revis. Eleotriformes, 68, 1875. 
Eleotris butis Day, Fishes India, 316, pl. Lxvm, fig. 3 (not good), 1878-88; Ganges. Giinther, Cat., m1, 116, 1861 (in part, only, 
perhaps). 
Butis leucurus Jordan & Seale, Proc. U. 8S. Nat. Mus., XxXv11, 1905, 794, fig.; Negros, P. I. Evermann & Seale, Bul. U. 8. 
Bureau of Fisheries, xx v1, 1906 (1907), 104; Bacon and San Fabian, P. I. 
Head 3 in length without caudal; depth 5; in total length, including caudal, 6; depth of caudal 
peduncle 3.30 in head; eye 5.50 in head, 1.50 in interorbital space; interorbital space 4 in head; maxil- 
lary 2.50 in head, greater than nose, extending past front of orbit under its anterior third; teeth small, in 
bands in both jaws, the outer ones slightly enlarged; dorsal vi-9; anal 9; scales 29; secondary scales present 
at base of large ones; color brown, with a few small spots on sides and under part of head, and scattered 
ones on body; scales of sides each with a pale spot at center, these appearing to form longitudinal rows, 
dorsals blackish, edged with pale; upper edge of caudal whitish, the rest dusky; anal blackish, with a 
trace of pale at edge; pectoral base with a black spot, above and below which are smaller white ones. 
This species differs from Butis amboinensis (Bleeker) in its less slender form, its broader interorbital 
space, and in the presence of secondary scales at the bases of the large scales on the sides. From Butis 
prismaticus (Bleeker) it is distinguished by its shorter maxillary, rather coarser teeth, and slenderer caudal 
peduncle. The three species, butis, prismaticus, and amboinensis, all have the superorbital crests weakly 
serrated or crenulate, differing widely in that respect from Butis (Prionobutis) koilomatodon (Bleeker). 
The statement in the original description of Butis leucurus Jordan and Seale, that the superorbital crests 
are smooth, was apparently made in a comparative sense, with reference to the condition in Butis koilo- 
matodon. It also seems that the interorbital distance in Butis leucurus was measured between the inter- 
orbital crests in the preparation of the original description of that species. 
Of this species we have two specimens, one 3.50 inches long from Manila, and one 3 inches from 
Tloilo. 
247. (?) Butis prismaticus (Bleeker). 
(?) Eleotris prismatica Bleeker, Blenn. & Gob., 23, 1849; Maduras Straits. 
(2?) Butis prismatica Bleeker, Revis. Eleotriformes, 61, 1875. 
Head 3 in length without caudal; depth 4 to 4.50; in total length, including caudal, 5 to 5.59; depth 
of caudal peduncle 2.80 in head; eye 6 to 6.50 in head, 1.65 to 2 in interorbital space; interorbital space 
3.75 to 4 in head; maxillary 2.75 in head, slightly greater than nose, not extending beyond the vertical 
from front of orbit; teeth minute, in bands in both jaws, outer ones not enlarged ; dorsal vi-9; anal 9; scales 
29; secondary scales present; color as.in Butis butis. 
A specimen from Cuyo, 5.50 inches long, and one from Manila, 3.50 inches, are referred with some 
doubt to the present species. They are plainly distinguished from Butis butis by their shorter, more 
robust body, shorter maxillary, smaller eye, and finer teeth. Both the present species and Butis butis 
are easily separated from Butis amboinensis, which is a very slender fish, with narrow interorbital space, 
and without secondary scales. 
