THE FISHES OF PORTO RICO. 
10b 
Carnivorous or herbivorous fishes; 4 genera and about 65 species, abounding in all warm seas, 
mostly pelagic, swimming near the surface, and skipping or sailing through the air, sometimes for 
considerable distances. 
a. Roof of mouth (vomer, palatines, pterygoids) and tongue provided with teeth, body not angular in outline (ellip- 
tical in cross section); pectoral fins moderate, not reaching beyond middle of dorsal fin, ventrals rather long, 
inserted behind middle of body; dorsal fin elevated; anal long, its base scarcely shorter than that of dorsal. 
Parbxocostus, 36 
aa. Roof of mouth and tongue with fewer teeth or none (vomer and palatines toothed or not); body angular in outline 
(a cross section subquadrate); pectoral fins very long, their tips usually reaching nearly to base of caudal, 
lower jaw little prominent; snout short. 
b. Ventral fins inserted anteriorly, much nearer tip of snout than base of caudal, not used as organs of flight, their 
tips not reaching nearly to front of dorsal; anal fin long, its base nearly equal to that of dorsal Exoccetus 
bh. Ventral fins inserted posteriorly, usually nearer base of caudal than tip of snout, used as organs of flight, their tips 
reaching past middle of base of anal. 
c. Anal fin long, its base a little less than that of dorsal, its origin nearly opposite that of dorsal Exonautes 
cc. Anal fin short, its base one-half to two-thirds that of dorsal, its origin behind that of dorsal CYPSiLUP.us r 37 
Genus 36. PAREXOCCETUS Bleeker. 
Body moderately elongate, elliptical in cross section. Snout short; lower jaw not produced. Roof 
of mouth (vomer, palatines, and pterygoids) fully provided with teeth; pectoral fins moderate, not 
reaching beyond middle of dorsal; ventrals long, inserted behind middle of body; anal fin about as 
long as dorsal; dorsal high. 
Small flying-fishes of tropical coasts, widely distributed. 
53. Parexocoetus mesogaster (Bloch). Volador; Flying-fish. 
Head 4.4 in length of body; depth 5; D. 12; A. 13; about 38 scales in lateral line, 5 rows of 
scales between lateral line and dorsal fin. Body elongate, compressed (not angulated), rather deep; 
width of body at base of pectorals 2 in head; head narrow, compressed, almost trenchant below; inter- 
orbital area flattish, about as wide as eye, 3 in head. Snout short, rather pointed, its length 4.25 in 
head; teeth on tongue and palatines; gillrakers numerous, long and slender; pectoral fins of moderate 
length, their length 1.66 to 2 in length of body, their tips reaching middle of base of dorsal fin; second 
ray of pectoral divided; dorsal fin very high, its longest rays about 0.16 longer than head; base of 
dorsal about 1.14 in length of head; tips of anterior rays of dorsal reaching beyond tips of posterior 
rays when fin is deflexed, almost to base of caudal fin; ventrals rather short, 4.75 in length of body, 
their tips reaching slightly past origin of anal fin; origin of ventrals midway between pupil and last 
caudal vertebra; anal fin opposite dorsal; lower lobe of caudal rather short, slightly longer than head. 
Color, blue above, silvery below, pectoral (dusky in the young) becoming nearly white in the 
adult; color of ventrals very similar to pectoral, the duskiness in the young formed of fine blaekish 
dots; upper half of anterior rays of dorsal fin black; anal fin with few small black dots, more numerous 
in the young; caudal dusky-reddish. 
This species reaches a length of 7 inches. It is common in the tropical seas of both the East 
Indies and West Indies, and in the Hawaiian Islands. It ranges north in the Gulf Stream to Rhode 
Island and is the most common flying-fish of the Carolina region. The young often has one or two 
fleshy barbels on the tip of the low'er jaw, these being fragile and easily destroyed. 
During the voyage of the Fish Hawk to Porto Rico and return to Norfolk, flying-fish were seen 
nearly every day and were particularly abundant between Savannah and the Bahamas, in the Wind- 
ward and Mona passages, and along the north coasts of Cuba, Santo Domingo, and Porto Rico. 
Scarcely a day passed when schools of twenty to a hundred or more did not follow along abreast of the 
ship. They were more numerous on bright days when there was considerable wind and the sea was 
somewhat rough. Apparently two or more species were seen, though the vast majority probably 
belonge to this species which seems to come nearer to shore than any other. A specimen 5.5 inches 
long flew aboard the ship at Aguadilla January 18. 
E.ioctrAu mesogaster Bloch, Ichthyolgia, pi. 399, 1795, Martinique; on a poor drawing by Plunder. 
Exoccetus orbignianus Cuvier & Valenciennes, Hist. Nat. Poiss., XIX, 131, 1846, Montevideo, based on a drawing. 
Exoccetus hillianus Gosse, Nat. Sojourn, in Jamaica, II, pi. 1, fig. 1, 1851, Jamaica. 
Exoccetus gryllus Klunzinger, Pische des Rothen Meeres, 586. 1870, Red Sea. 
Parexocoetus mesogaster Jordan & Evermann 1. e., 728, 1896. 
