THE FISHES OF PORTO RICO. 
287 
hh. Post-temporal bopes very strongly divergent, their insertions close together, distance between them about two- 
thirds the narrow interorbital space, and less than one-seventh length of head; top of skull somewhat elevated 
and declivous; interorbital area somewhat convex transversely; lower pharyngeals rather broad, teeth bluntish: 
pfeopercle with partly concealed spine directed downward and forward at its angle; scales moderate, 45 to 60 
in a longitudinal series Eleotris, 136 
g<j. Body very slender, elongate, depth 8 to 9 times in length to base of caudal; scales very small, cycloid. 
i. Preopercle without spine; caudal without many accessory rays at base; post-temporal bones short, strongly 
divergent, distance between their insertions about equal to narrow interorbital space, or about one-sixth length 
of head; top of head with a strong median keel, which is highest on occipital region; no supraoecipital crest, 
mouth very oblique; teeth small Erotelis 
aa. Ventral fins united. 
j. Dorsal fins separate, free from caudal. 
Sicydiin*: 
k. Ventral disk short, adnate to belly; body subcylindrical, covered with ctenoid scales; lips very thick; upper teeth 
mostly small and movable, lower fixed; dorsal spines 6. Teeth simple; no canines in front of lower jaw. 
Sicydium, 137 
GOBiiNa:: 
kk. Ventral disk free from the belly. 
1. Dorsal spines 4 to 8; eyes well developed. 
to. Teeth emarginate, uniserial, those of lower jaw nearly horizontal; dorsal spines 6; scales large, ctenoid; gill- 
openings moderate Evorthodus 
toto. Teeth simple. 
n. Body scaly, more or less. 
o. Maxillary normal, not prolonged behind rictus; skull of usual gobioid form, comparatively short and abruptly 
broadened behind orbits; occiput depressed; supraoecipital and temporal ridges continuous. 
p. Dorsal spines 6; scales evidently ctenoid; head naked (nape scaly as usual). 
q. Interorbital area anteriorly elevated, with a large foramen-like depression in front of eye; body short, compressed, 
formed much as in Dormilator; nape with a fleshy crest; scales large. Vertebrae 11 + 15 Lophogobitjs 
qq. Interorbital area not elevated in front; body more elongate; no fleshy nuchal crest; isthmus broad. 
r. Inner edge of the shoulder-girdle without fleshy cirri or papillae; cranium anteriorly short; interorbital space 
narrower, grooved, with a low median ridge or none; median crest on cranium low. 
s. Body scaly anteriorly and posteriorly (sometimes a naked strip on back or belly). Vertebrae 12 + 16 to 
10 + 15 Gobius, 138 
ss. Body entirely naked anteriorly, posterior half scaled; scales moderate or small Garmannia 
rr. Inner edge of shoulder-girdle with 2 or 3 conspicuous dermal flaps; preorbital region very long; premaxillary and 
maxillary strong; interorbital groove with a conspicuous median crest; scales rather small (45 to 70) . Awaous, 139 
pp. Dorsal spines 7 or 8 (very rarely 6, especially in Eucyclogobius) . 
1. Scales large, ctenoid; shoulder-girdle without dermal flaps. Sides of head scaled; soft dorsal and anal rather 
short, of 11 to 14 rays each; deep-water species Bollmannia, 140 
tt. Scales very small, cycloid or nearly so. Inner edge of shoulder-girdle without fleshy processes; head naked; body 
more or less compressed; mouth very oblique; teeth strong; interorbital groove with or without a median ridge. 
Vertebrae 11+15 or 16; soft dorsal and anal long, of 15 to 17 rays each. Body chiefly scaly, anteriorly as well as 
posteriorly Microgobius, 141 
nn. Body and head entirely naked. Dorsal spines 7 (rarely 6). 
u. Chin without barbels; mouth small, little oblique; body robust, soft dorsal and anal short Gobiosoma 
uu. Chin with a fringe of short barbels; mouth terminal, oblique; soft dorsal and anal very short Barbclifer 
jj. Dorsal fin continuous, soft part and anal joined to base of caudal; eye minute; body elongate; scales minute or 
wanting; mouth very oblique, lower jaw projecting; gill-openings moderate. 
v. Dorsal rays vi, 16 to 23; anal rays 17 to 23. Teeth in a band, those of outer series being very strong; scales present. 
w. Body entirely scaled Gobioides, 142 
ww. Anterior part of body naked Cayennia 
Genus 133. PHILYPNUS Cuvier & Valenciennes. Guavinas. 
Body elongate, terete anteriorly, compressed behind. Head elongate, depressed above. Mouth 
large; lower jaw considerably projecting; teeth in jaws rather small, slender, recurved, outer scarcely 
enlarged; teeth on vomer villiform, in a broad, crescent-shaped patch; gill-openings extending forward 
to below posterior angle of mouth, isthmus very narrow. Scales moderate, ctenoid, covering most of 
head, 55 to 66 in a longitudinal series. Dorsal with 6 spines and 9 or 10 rays; anal rays i, 9 or 10; 
ventrals separate. No preopercular spine; insertion of post-temporals almost midway between occipital 
crest and edge of skull; parietals with a crest running from insertion of post-temporal forward to just 
behind eye, where they are connected by a thin, high, transverse crest; supraocular with a short, high 
crest, extending from above front of eye back to posterior edge of orbit, thence extending outward 
parallel with transverse crest, leaving a deep groove between them; bony projections before and behind 
eye prominent. Vertebrae 12 + 13=25; lower pharyngeals triangular, with slender teeth. 
The fishes of this genus are the largest of the gobies, some reaching a length of 2 or 3 feet and 
being valued as food. Found in tropical rivers. 
