FISHFS OF HAWAIIAN ISLANDS. 
407 
skeleton imperfectly ossified, the number of vertebrae usually small, typically fewer than 24 (usually 
14 to 20), rarely considerably increased. Gill-openings restricted to the sides; ventral fins reduced 
or wanting, the pelvic bones usually elongate; spinous dorsal small or wanting; air-bladder without 
duct. Fishes chiefly of the Tropics, mostly inactive and depending on their tough skin or bony or 
spinous armature for their protection. 
a. Jaws with distinct teeth. 
6. Spinous dorsal present; body with scales or movable plates Sclerodermi, p. 107 
bb. Spinous dorsal wanting; body encased in an immovable carapace of hexagonal plates; the jaws, bases of fins, and tail 
only free - Ostracodermi, p. 441 
aa. Jaws modified into a sort of beak, each with an enamel-like covering and without distinct teeth; scales rhomboid or 
spiniform, with root-like insertions; spinous dorsal wanting Gymnodontes, p. 424 
Suborder SCLERODERMI. 
The Sclerodermi may be defined as Plectognathous fishes with a spinous dorsm composed of one 
or more spines inserted just behind the cranium; body of the normal fish-like shape; scales rough, or 
spinigerous, of regular form; jaws with distinct teeth, conical or incisor-like. 
a. Ventral fins obsolete, or the pair represented by a single spine at the end of the long pelvic bone; scales rough , rhombic, 
or spiniform. 
b. Vertabra in small number, 17 to 21; no barbel at chin; gill-opening not before the eyes. 
e. First dorsal composed of 3, rarely 2, spines; the first spine very large, the second locking it in erection; scales com- 
paratively large, bony, rough, forming a coat of mail; vertebra 17 Balistidse , p. 407 
cc, First dorsal of a single spine, with a rudiment at its base; scales minute, not bony, the edges spineseent, so that the 
surface of the body is rough velvety; vertebra 18 to 21 Monacanthidaz , p. 418 
Family LXXVI. BA USX 1 D4L — Trigger-fishes. 
Body oblong or ovate, moderately compressed, covered with rather large, rough scales or scutes 
of various forms, not forming an immovable carapace; lateral line obscure or wanting; mouth small, 
terminal, and low; jaws short, each with about 1 series of separate, incisor-like teeth; eye near occiput; 
preorbital very deep; no barbels; gill-openings small, slit-like, above or in front of pectoral fins, not 
before eyes; dorsal fins 2, the anterior of 2 or 3 spines, the first highest and very strong, the second 
locking it in erection; second dorsal remote from the first, of many soft rays. Shore fishes of the 
tropical seas, of rather large size, carnivorous or partly herbivorous, very rarely used as food, many of 
them reputed to be poisonous. 
a. Caudal peduncle compressed. 
b. Teeth white or pale, not red. 
c. Teeth unequal, oblique, each one deeply notched. 
d. Gill-opening with a number of enlarged bony plates or scutes behind it; ventral flap movable, supported by a 
series of spines, more or less free at tip and resembling fin rays; cheeks entirely scaled, without naked 
grooves or patches. 
e. Eye with a preocular groove Batistes, p. 407 
ee. Eye without preocular groove; caudal scales spinous Balistapus, p. 413 
dd. Gill-opening with only ordinary scales behind it. 
h. Chin not projecting; cheeks closely scaled; dorsal spines 3; scales of posterior parts unarmed or keeled 
- Canthidermis , p. 415 
hh. Chin much projecting; cheek with 3 to 5 narrow parallel grooves; dorsal spines 2; scales of posterior parts 
more or less keeled Xanthichthys, p. 416 
cc. Teeth even, incisor-like Melichthys, p. 417 
Genus 184. BALISTES (Artedi) Linnaeus. Trigger-fishes. 
Body compressed, covered with thick, rough scales or plates of moderate size, 50 to 80 in a length- 
wise series; a naked groove before eye below nostrils; lateral line more or less developed, very slender, 
undulate, conspicuous only when the scales are dry, extending on the cheeks; pelvic flap large, mov- 
able, supported by a series of slender, pungent spines; caudal peduncle compressed, its scales armed 
or unarmed, with or without spines or differentiated tubercles similar to those on rest of body; gill- 
opening with enlarged bony scutes behind it; cheeks entirely scaly, without naked patches or grooves; 
each jaw with irregular, incisor-like teeth, usually 4 on each side in each jaw: first dorsal of 3 spines, 
the anterior of which is much the largest, the second acting as a trigger, locking the first when erected; 
