THE FISHES OF PORTO RIOO. 
253 
This is a very handsome fish and, like the rock beauty, appears very striking when seen swim- 
ming leisurely in the clear water about the coral reefs. It is known from southern Florida through 
the West Indies to Brazil; it has been recorded from the Tortugas, Key West, the Bahamas, Cuba, 
Jamaica, the Bermudas, the Lesser Antilles, and Bahia. Specimens 9 to 13 inches long were obtained 
by us at Ponce and Culebra, and it is doubtless a common species about Porto Rico. At Key West 
it is probably the most common of the 4 angel-fishes occurring there, ft attains a good size (1 to 2 feet 
in length) and is a fair food-fish. Like all similar fishes, it is usually caught by traps, though it some- 
times takes a baited hook. 
Angel-fish, Catesby, Nat. Hist. Carolina, etc., 1737. 
Tsabelita , Parra, Dif. Piezas, etc., 1787, Cuba. 
Chastodon ciliaris Linnaeus, Syst. Nat., ed. X, 276, 1758, Indies; in part. 
Chidodon squamulosus Shaw, Naturalists’ Miscellany, 275, 1789-1813; after Angel-fish of Catesby. 
Chxlodon parrse Bloch & Schneider, Syst. Ichth., 235, 1801, Cuba; after Isabelita of Parra. 
Holacanlhus eornutus Desmarest, Decade Ichthyologique, 44, pi. 3, fig. 3, 1823, Cuba. 
Holacanthus formosus Castelnau, Anim. Nouv. ou Rares de 1’ Amer. du Sud, Poissons, 19, pi. 2, fig. 2, 1855, Bahia. 
Angelichlhys ciliaris, Jordan & Evermann, 1. c., 1684, 1898. 
Family LV. TEUTHIDIDIE. The Surgeon-fishes. 
Body oblong, compressed, and usually elevated, covered with very small scales; lateral line 
continuous. Tail armed with one or more spines or bony plates. Eye lateral, high up; preorbital very 
narrow and deep. Nostrils double. Mouth small, low; each jaw with a single series of narrow incisor- 
like teeth; vomer and palatines toothless; premaxillaries somewhat movable, but not protractile; 
maxillary short, closely united with premaxillary; gillrakers obsolete; pseudobranch ite large; gills 4, 
a slit behind fourth; gill-membranes attached to isthmus, openings thus restricted to sides. A single 
dorsal fin, with strong spines, spinous part of fin shorter than soft part; anal fin similar to soft dorsal; 
pectoral moderate; ventral fins present, thoracic, mostly i, 5, never i, 4, x. Pelvic bones long, narrow, 
curved, closely connected, evident through skin, as in Balislidx, with which group the Teuthididie have 
the closest affinities. Pyloric caeca rather few; air-bladder large; intestinal canal long. Vertebrae 
9 -)- 13 = 22. Posterior suborbital bones in close contact with preopercle; post-temporal immovably united 
with skull, apparently simple, but really trifurcate, with interspaces filled in with bone, the foramen 
not passing through it; interneural bones with transversely expanded buckler-like subcutaneous plates, 
which intervene between spines and limit their motion forward; epipleurals developed from ribs. 
Herbivorous fishes of the tropical seas. 
Genus 117. TEUTHIS Linnaeus. The Tangs. 
This genus includes those Teuthididie which have the tail armed with a sharp, antrorse, lancet- 
like, movable spine; strong, fixed, incisor teeth; ventral rays i, 5, and usually 9 spines in dorsal fin. 
The numerous species are found in all tropical seas. Herbivorous fishes, living about coral reefs; adult 
protected by the murderous caudal spine, which grows larger with age. Of the six species of this genus 
known to occur in America north of the Equator, three are known from Porto Rico. 
а. Outline rhomboid, depth 1.5 in length; color brown, washed with deep blue cieruleus, 211 
aa. Outline ovate, depth about 2 in length; color brown, never blue. 
б. Caudal simply lunate hepatus, 212 
66. Caudal deeply emarginate. Upper lobe of caudal produced in a filament baluanus, 213 
211. Teuthis cceruleus (Bloch & Schneider). “Medico”; Bcirbero; Blue Tang. 
(Plate 38.) 
Head 3.4; depth 1.75; eye 4.5; snout 1.3; interorbital width 3; preorbital 1.67; D. ix, 26; A. in, 
25. Body rhomboid, anterior profile subvertical, nearly straight, making an angle of about 60° with 
axis of body; dorsal outline from origin of dorsal fin to caudal peduncle a gentle convex curve; ventral 
outline a regular curve from snout to caudal peduncle; mouth slightly below axis of body; least depth 
of caudal peduncle 2 in snout. Dorsal fin moderate, longest spines about 2.4 in head, a little shorter 
than longest rays; longest anal rays about 2.75 in head, longest anal spine 2; pectoral long, slightly 
falcate, as long as head; ventrals 1.5 in head; caudal deeply lunate, its lobes subequal, middle lays 
about half length of outer, which are about a sixth longer than head. 
Color, rich blue throughout, body with about 45 or 50 narrow longitudinal lines of lighter blue 
