THE EISHES OF PORTO RICO. 
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whole length, separated by interspaces of similar width; margin of caudal fin bluish, with a violet base; 
no distinct dark crossbar at base of caudal. A young individual, less than 3 inches long, had sides 
bluish-brown, with numerous fine, wavy, darker brown longitudinal lines; dorsal, caudal, and anal fins 
bluish, with darker blue border, caudal palest; pectoral pale; ventrals darker blue; caudal spine bluish. 
Though not the most abundant species of the genus, the ocean tang is the most val Liable of those 
found in our waters. It occurs throughout the West Indies and on neighboring coasts of tropical 
America from southern Florida to Brazil. It has been recorded from Key West, Havana, and Bahia. 
It is the least common of the three species found at Key West, but about Porto Rico it is the second in 
abundance. Specimens are in the collections from San Juan, Aguadilla, Mayaguez, Ponce, Arroyo, 
Hucares, Fajardo, Isabel Segunda, Culebra, and San Geronimo. Large examples were observed in 
greatest numbers at Culebra, where this was one of the most common fishes seen in the fishermen’s boats. 
A pot or trap basket lifted in our presence by a Tortola fisherman contained 30 good-sized examples 
of this species, and many others had been taken from the other pots. 
The ocean tang apparently reaches the largest size of any of the three species (a foot or more), and 
is by far the most important as a food-fish. It is held in high esteem by the fishermen from Tortola, 
St. Croix, and St. Thomas who come to the Porto Rican waters. It is usually caught in the common 
native trap basket or pot, which is baited with large chunks of the white pulp of the cactus and set in 
4 to 10 fathoms of water. Sometimes the fish are “grained,” or speared, and occasionally they are 
taken with hook and line. This is one of the principal fishes that are corned (so that they will keep 
well for about two weeks) , and taken chiefly to Santa Cruz, where they bring about $5 a barrel. 
Acanthurus baldanus Castelnau, Anim. Nouv. ou Rares de l’Amer. Sud, 24, pi. 11, fig. 1, 1855, Bahia. 
Acanthurus tractus Poey, Mem., II, 208, 1860, Cuba; Poey, Fauna Puerto-Riquefia, 330, 1881; Stahl, 1. c., 77 and 164, 1883. 
Acronurus nigriculus Poey, Enumeratio, 69, 1875, Cuba; larval form. 
Teuthis bahianus, Jordan & Evermann, 1. c., 1693, 1898. 
Fig. 70. — Teuthis bahicmus. 
Family LVI. BALlSTIDAi. The Trigger-fishes. 
Body oblong, or ovate, moderately compressed, covered with rather large rough scales or scutes 
of varying form, scutes not forming an immovable carapace. Lateral line obscure or wanting. Mouth 
small, terminal, low; jaws short, each with about one series of separate incisor-like teeth; eye near 
occiput; preorbital very deep. Chin without barbel. Gill-openings small, slit-like, above or in front 
of pectoral fins, and not before eyes. Dorsal fins 2, anterior of 2 or 3 spines, first spine highest, very 
strong, second locking it in erection; second dorsal remote from first, of many soft rays; caudal fin 
rounded or forked; ventral fins wanting, their place occupied by a single stout thick spine at end of 
the very long, usually movable, pubic bone. Post-temporal short, simple, forks obliterated, bone 
grown solidly to skull, and without foramen. Vertebrae in reduced number (17). 
