124 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
83. Tylosurus giganteus (Schlegel). “Ahaciha;” “Auau.” Fig. 39. 
Head a little over 2 in trunk; depth 9.5 in trunk; D. 24; A. 22; P. 14; V. 6; scales about 370 or 
more to base of caudal; depth of head a little more than its greatest width; eye about 2.13 in post- 
ocular part of head, 1.3 in interorbital space; pectoral about 3.5 in space between tip of snout and 
opercle; ventral 3.85. 
Body elongate, more or less rounded, the sides a little compressed; head long, flattened above, 
the sides compressed, somewhat constricted below; eye moderate, a little longer than deep; jaws long, 
strong, and rather powerful, the lower a trifle the longer; groove of maxillary extending posteriorly 
for nearly half the eye diameter; teeth developed as large canines in both jaws, and with villiform 
bands along the edges; also a median roughened ridge on the mandible; no vomerine teeth; tongue small, 
blunt, little free in front, and fleshy; nasal cavity large, close to upper margin of eye and with a thick 
fleshy flap over the nostril; interorbital space broad, slightly convex; top of head with bony striae; 
gill-openings large, the isthmus very narrow, long and thin; no gillrakers; no pseudobranchise; peri- 
toneum gray; scales very small, narrowly imbricated, very much smaller on back than elsewhere; no 
tin flaps ; cheek scaled, a few scales on top of head, but opercles bare; lateral line running inferiorly 
along side and up on side of caudal peduncle; origin of dorsal nearer that of ventral than base of caudal 
by about length of pectoral, the origin of anal only slightly in advance; anterior dorsal rays elongate, 
those forming posterior half of fin rather long, but shorter than the former; anterior anal rays form- 
ing a rather long lobe; caudal rays strong, deeply emarginate, lower lobe the longer, length of fin 
about 2.3 in entire length of head; pectoral rather small, upper ray enlarged; ventrals inserted nearer 
base of pectoral than base of caudal by a space equal to that between middle of eye and posterior mar- 
gin of opercle; least width of caudal peduncle only a trifle more than its least depth, the keel along 
side more or less obsolete. 
Fig. 39. — Tylosurus giganteus (Schlegel); after Bleeker. 
Color in alcohol more or less silvery white below, the upper surface greenish brown; fins tinted 
with yellowish about their bases. 
This description taken from an example (No. 05006) 18 inches long obtained at Honolulu. We 
have others taken at Honolulu, one by Dr. Jenkins in 1889. In an example from Hilo the color 
markings are better preserved. It has a dark or blackish lateral band from over pectoral to near base 
of caudal, the dorsal, caudal, and pectoral are more or less blackish, and the margin of the preopercle 
is broadly marked with blackish brown. 
This fish reaches a rather large size, one of our numerous examples being 40 inches long. It is a 
food-fish of considerable importance, living in the open sea. 
Belone gigantea Schlegel, Fauna Japonica, Poiss., 245, 1846, Nagasaki, Japan. 
Belone annulata Cuvier & Valenciennes, Hist. Nat, Poiss., XVIII, 447, pi. 550, 1846, Celebes, Tongatabu, Seychelles, Pondi- 
cherry; Gunther, Cat., VI, 240, 1866 (Pinang, China, Formosa, Gilolo); Steindachner, Denks. Ak. Wiss. Wien, LXX, 
1900, 512 (Honolulu; Samoa). 
Belone melcinurus Bleeker, Verh. Bat. Genoot., XXII, 1849, 11, Madura, Madura. 
Belone cylindrica Bleeker, Verh. Bat. Genoot., XXIV, 1852, 13, Bijd, Soend. 
Mastacembelus choram Bleeker, Ned. Tyds. Dierk., Ill, 1866, 227, East Indies. 
Mastacembelus annulatus , Bleeker, Atlas Ichth., VI, 48, pi. 258, fig. 3, 1869-71 (Java, Madura, Bawean, Cocos Island, Sumatra, 
Singapore, Pinang, Bangka, Celebes, Batjan, Ternate, Amboyna). 
Tylosurus annulatus, Seale, Occas. Pap. Bishop Mus., I, 64, 1901 (Guam). 
Tylosurus giganteus, Jenkins, Bull. U. S. Fish Comm., XXII, 1902 (Sept. 23, 1903), 433 (Honolulu). 
