184 ON THE FISHES OF THE GENUS TRIACANTHUS.  [ Feb. 17, 
orbital part of head equal to or greater than eye-diameter. Inter- 
orbital space with a more or less distinct median ridge, with a 
groove on each side of it. Occipital crest convex, moderately 
elevated, becoming nearly horizontal in front of the base of the 
first dorsal spine. D. V, 24-25; A. 18-20; first dorsal spine 
shorter than the head, the others short; length of base of anal fin 
12-12 times in that of soft dorsal fin; pelvis between ventral 
spines broad, scarcely narrowed posteriorly. Membrane of spinous 
dorsal fin blackish. 
Total length 250 mm. 
Hab. Kast Indian Archipelago, Seas of China and Japan. 
TRIACANTHUS INDICUS, 0. Sp. 
Russell, Indian Fishes, p. 14, pl. xxi. (1803). 
Balistes biaculeatus Bennett, Fishes of Ceylon, pl. xv. (1830). 
Triacanthus biaculeatus Cantor, Mal. Fish. p. 360 (1847); Day, 
Fishes of Malabar, p. 260 (1865). 
Triacanthus brevirostris Hollard, Ann. Sci. Nat. (4)1. 1854, p. 45, 
pl. ii. fig. 1; Giinther, Cat. vii. p. 209, part. (1870); Day, Fishes 
of India, p. 685, pl. clxxv. fig. 1°(1878). 
Depth of body 23-2 times in the total length, length of head 
31-34 times, length of caudal peduncle 47-5 times. Snout 
straight, its length about 1? times in that of the head, eye-diameter 
3-43 times, interorbital width 3-3? times. Length of post- 
orbital part of head distinctly less than eye-diameter. Interorbital 
space with a more or less distinct median ridge with a groove on 
each side of it. Occipital crest elevated, its upper edge nearly in 
the same straight line with that of the snout. D. V, 24-25; 
A. 18-20; first dorsal spine nearly as long as the head, the others 
short ; length of base of anal fin 14-14 times in that of soft dorsal 
fin; pelvis between ventral spimes broad, scarcely narrowed 
posteriorly. Membrane of spinous dorsal fin blackish. 
Total length 220 mm. 
fab. Coasts of India from Kurrachee to Penang; Ceylon ; 
Andaman Is, 
This species differs from 7. brevirostris chiefly in the longer 
snout, the shorter postorbital part of head, and the shorter and 
more elevated occipital crest. The figures given by Russell and 
Bennett are excellent. 
TRIACANTHUS NIEUHOFI. 
* Nieuhof, Gedenkw. Zee en lantr. p. 272, fig. 
Willoughby, Ichthyology, Appendix, p. 5, pl. x. fig. 2 (1686). 
? Gronow, Mus. 1. p. 52 (1754-6) & Zoophyl. p. 53 (1763-81). 
Triacanthus nieuhofi Bleecker, Verh. Bat. Gen. xxiv. 1852, p. 26, 
pl. iv. fig. 9, & Atlas Ichth. v. p. 92, pl. cexvii. fig. 3 (1865). 
Triacanthus brachysoma Bleeker, Nat. Tijds. Ned. Ind. tv. 
1853, p. 128. 
1 T have not been able to verify this reference. 
