THE FISHES OF PORTO RICO. 
G1 
Family III. GALElDAt. The Requiem Sharks. 
Sharks with two dorsal tins, first short and high, entirely before ventrals; second comparatively 
small, opposite anal ; no spines; gill-openings moderate, the last above base of pectoral; tail moie or 
less bent upward from base of caudal fin; sides of tail not keeled; eyes with nictitating membrane.'; 
head not hammer-shaped, the snout being longitudinally produced, as usual among sharks. Spiracles 
small or obsolete. Ovo viviparous. 
A large family of 20 or more genera and about 60 species; found in all seas. The species are often 
closely related and difficult of determination. Of 11 genera recognized by Jordan & Evermann as 
occurring in American waters, only one is as yet known from Porto Rico. 
Galeims: 
а. Teeth flat and paved, without cusps or ridges; spiracles present; no pit at root of tail; labial folds well developed. 
б. Embryo not attached to uterus by a placenta; teeth very blunt Mustei.us 
an. Teeth more or less compressed, with entire or serrate sharp edges. 
Galeorhininjs: 
c. Spiracles present. 
d. Root of tail with conspicuous pit above; teeth all coarsely serrate, alike in both jaws and each with a deep notch 
on outer margin; caudal fin with a double notch Galeocerdo 
CARCHARHININiE: 
cc. Spiracles obsolete; lower teeth narrower than upper teeth. 
e. Angle of mouth without groove or with merely a slight depression, which does not extend along either jaw. 
/. First dorsal inserted anteriorly, nearer ventrals than pectorals; embryo (so far as known) attached to uterus by a 
placenta. 
g. Teeth all serrate more or less, often entire in the very young Carcharhinus, 4 
gg. Teeth of upper jaw serrate at base only; lower teeth entire, erect Hypoprion 
gyg. Teeth all entire at all ages, and nearly all erect Aprionodon 
ee. Angle of mouth provided with a more or less distinct groove which extends along one or both jaws; teeth entire, 
or very nearly so, more or less obliquely placed, their points turned away from median line: embryo (so far as 
known) with a placenta Scoliodon 
Genus 4. CARCHARHINUS Blainville. 
Body rather robust; head broad and depressed; mouth inferior, with teeth in both jaws strongly 
serrated in adult, less so or entire in young, those in upper jaw broad or narrow, those below narrow, 
straight, and nearly erect. No spiracles. First dorsal large, not far behind pectorals; pectoral falcate; 
second dorsal small. Embryos attached by placenta to uterus, as in Scoliodon, Triakis, and Galeus. 
Voracious sharks of the warm seas. Species very numerous and difficult of separation. 
a. Teeth in both jaws distinctly serrate in adult; serrae on lower teeth smaller; upper teeth rather broad, lower teeth 
narrower; snout not very acute. 
Platypodoh : 
b. Upper teeth oblique, deeply notched on outer margin; lower teeth narrow, scarcely or not notched. 
c. Pectoral very large, 3 times as long as broad, falciform, extending beyond base of first dorsal; color blue- 
gray obscurus 
cc. Pectoral shorter, not 3 times as long as broad, extending little if any beyond base of first dorsal. 
d. Length of snout from mouth little if any greater than width of mouth. 
e. Distance from end of base of first dorsal to ventrals less than length of base of first dorsal. 
/. Nasal flap without sharp lobe; second dorsal and anal nearly equal; color blue-black falciformis, 4 
ff. Nasal flap with an acute lobe. 
g. Snout not very short, its length from the mouth not notably less than the width of mouth; color yellowish- 
brown acronotus 
gg. Snout very short and blunt, its length from mouth but two-thirds width of mouth perr.i 
ee. Distance from end of base of first dorsal to ventrals greater than length of first dorsal; snout moderate remotus 
dd. Length of snout from mouth greater than width of mouth; first dorsal small lienlei 
Carcharhinus ; 
bb. Upper teeth triangular, suberect, scarcely notched on the outer margin; lower teeth similar but much narrower. 
h. Snout moderate, its length from mouth about equal to width of mouth milberti 
hli. Snout very short, its length from mouth less than width of mouth. 
i. Pectoral long and falcate, reaching to posterior part of base of dorsal. Anterior margin of first dorsal convex, height 
of fin about equal to depth of body lamia 
si. Pectoral fin moderate, scarcely falcate, not reaching to end of base of dorsal; second dorsal not larger than anal; 
length of snout from mouth 1.5 times in breadth of mouth; upper teeth very broad platyodon 
ISOGOMPHODON : 
aa. Teeth slightly serrated, similar in form in the two jaws, narrow, elaviform, constricted at base; snout rather sharp. 
j. Snout moderate, its length from mouth not greater than breadth of mouth; teeth moderate; fins edged with 
black limbatus, 5 
jj. Snout very long and narrow, its length from mouth twice distance between nostrils; teeth small, about 48 in each 
jaw oxyrhynchus 
