THE FISHES OF PORTO RICO. 
137 
This species ranges from Cape Cod to Brazil; it is very common on our south Atlantic coast and 
in Cuba, but is not valued as food, the flesh being thin and dry, the bones large. It is apparently not 
common in Porto Rico, specimens being obtained by us only at Mayaguez and Isabel Segimda. 
Scomber chrysurus Linnaeus, Syst. Nat., XII, 494, 17GG, Charleston, South Carolina. 
Scomber chluris Bloch, Iehthyologia, pi. 339, 1793. 
Micropteryx cosmopolite, Agassiz, Spix, Pise. Bras., 104, 1829, Brazil. 
Scomber latus Gronow, Catalogue Fishes, ed. Gray, 127, 1854, Carolina. 
Chloroscombrus caribbxus Girard, Mex. Bound. Surv.,Zool., 21, pi. 9, fig. 6, 1859, St. Joseph Island, Texas. 
C'Moroscombrus chrysurus, Poey, Fauna Puerto-Riquena, 332, 1881; Stahl, 1. e., 77 and 103; 1883; Jordan &Evermann, l.o., 
938, 1896. 
Genus 61. TRACHINOTUS Lacepede. The Pampanos or Pompanos. 
Body compressed, moderately elevated, general outline ovate. Caudal peduncle short and rather 
slender. Abdomen not trenchant, shorter than anal fin. Head moderately compressed, very blunt, 
snout abruptly truncate. Mouth nearly horizontal, the maxillary reaching middle of eye; premaxil- 
laries protractile; maxillary without distinct supplemental bone. Jaws, vomer, and palatines with 
bands of villiform teeth, which are deciduous with age. Preopercle entire in adult. Gillrakers short. 
Gill-membranes considerably united. Spinous dorsal represented by six rather low spines, which are 
connected by membrane in young, but are free in adult. In old examples the spines appear small on 
account of encroachments of flesh, and ultimately often disappear. Second dorsal long, elevated in 
front; anal opposite to it and similar in form and size; two stout, nearly free spines in front of anal, and one 
connected with the fin, these often disappearing with age. Scales small, smooth. Lateral line unarmed, 
little arched; no caudal keel. 
‘ ‘ When extremely young the preoperculum is armed at the angle with three large spines, and smaller 
ones above and below. The spinous dorsal is developed as a perfect fin, and teeth are present on the 
jaws and palatine arch. In this stage the species has never been described by previous naturalists, and 
consequently has received no name, as the corresponding stage of Naucrates ( Nauclerus ) has. At an 
early period the preopercular spines are absorbed into the substance of the preoperculum and disappear. 
The spinous dorsal and the teeth are still retained. In this condition it remains for some time, the 
spinous dorsal, however, gradually losing its relative size, while the soft vertical fins increase. In this 
stage the species belongs to the nominal genus Doliodon of Girard. At a later period the membrane con- 
necting the dorsal spines has become obsolete, and the species then represents the genus Trackinotus, as 
understood by Cuvier & Valenciennes and others. Finally, in old age, the teeth of the jaws, palate, and 
pharyngeal bones have fallen out, and the lobes of the dorsal, anal, and caudal fins attain their greatest 
extension and become pointed. This final stage has been made known by Holbrook under the new 
generic name of Bothrolmmus'” (Gill, Proc. Ac. Nat. Sci. Phila. 1862, 440). The pseudobranchise also 
disappear in old individuals. 
Some species of Trachinotus ( carolinus , etc. ) are among the most highly valued of our food-fishes. 
a. Dorsal with 19 or 20 soft rays; anal with 17 to 19 soft rays. 
b. Body very much compressed; sides with narrow black crossbars; lobes of vertical fins elongate, reaching past 
middle of caudal fin in adult glaucus, 96 
bb. Body moderately compressed; sides without narrow black crossbars; lobes of vertical fins shorter, rarely reaching 
base of caudal; lobes of dorsal and anal usually blackish. 
c. Body broad-ovate; back arched; greatest depth at all ages nearly two-thirds length of body; profile from nostril 
to dorsal everywhere nearly evenly convex; axil without black spot falcatus, 97 
cc. Body oblong, the profile not strongly arched; depth in young and old 2 to 2.6 in length of body; dorsal lobes 
low goodci 
an. Dorsal with 25 to 27 soft rays; anal with 22 to 26 soft rays; body oblong, rather robust; greatest thickness 3 in greatest 
depth of body; depth less than half length; lobes of vertical fins short, not black: sides without dark crossbars. 
<1. Dorsal with 25 soft rays; anal with 22 soft rays; profile from snout to procumbent spine evenly convex. 
e. Body very deep, depth about half length argenteus 
ce. Body moderately deep, depth about 2.5 in length Carolinus, 98 
(Id. Dorsal with 27 soft rays; anal with 26 cayennensis 
96. Trachinotus glaucus (Bloch). Gaff-lopsail; Pompano; Palometa. 
Head 4; depth 2; eye 3.6. D. vi-i, 19; A. ii-i, 18; pyloric cseca 13. Body elliptical, much 
compressed; snout blunt, subtruncate, vertical from mouth to horizontal from upper edge of the eye; 
profile from supraorbital to front of dorsal fin convex. Mouth nearly horizontal; maxillary nearly 
