THE FISHES OE PORTO EICO. 
73 
Family XIII. OPHICHTHYM. The Snake Eels. 
This family includes those enchelycephalous eels which are scaleless and have the end of the ia.il 
projecting beyond dorsal and anal fins, and without rudiment of a caudal fin. Anterior nostrils placed 
in upper lip, opening downward; gill-openings not confluent; tongue more or less fully adnate to floor 
of mouth. Species usually moderate or small in size, very abundant in tropical seas, especially about 
coral reefs. The eggs are numerous, of moderate size, similar to those of ordinary Ashes. 
Of 12 genera of this family occurring in America only 4 are known to have species in Porto Rico. 
a. Body without traces of fins anywhere; teeth all small, conical; gill-openings near together, subinferior; anterior 
nostril tubular; tongue scarcely free in front; mouth small. 
b. Gill-slits inferior, converging forward _ Sphagebranchus, 14 
bb., Gill-slits small, lateral, placed vertically Verma 
aa. Body with distinct fins, at least on back. 
c. Anal fin wholly wanting; no pectoral fin; dorsal fin high, beginning on head; gill-openings subinferior, converging; 
anterior nostrils tubular; tongue slender, somewhat free in front Letharchus 
cc. Anal fin well developed; anterior nostril usually in a short tube near tip of snout. 
d. Teeth blunt, mostly granular or molar; vomer with teeth; pectoral fins present, small. 
e. Dorsal rather high, beginning on head, before gill-opening Myrichthys, 15 
ee. Dorsal fin beginning behind gill-opening, fin usually low Pisoodonophis 
dd. Teeth all pointed, none of them molar; vomer with teeth. 
/. Dorsal fin beginning before nape, on anterior part of head; pectoral fin small or wanting. 
g. Pectoral fins wholly wanting; body compressed, dorsal fin high Callechelys 
gg. Pectoral fins small, but present; body elongate, subterete, dorsal fin moderate Bascanichthys 
ff. Dorsal fin beginning more or less behind gill-opening. 
h. Teeth subequal, with no elongate canines on jaws or vomer Ophichthus, 1C 
hh. Teeth unequal, some of them long canines, either on vomer or on sides of one or both jaws; mouth large, snout 
short, and eyes more or less superior Mystriophis 
Genus 14. SPHAGEBRANCHUS Bloch. 
This genus contains several little-known species of small eels remarkable for showing no trace of 
fins in the adult stage. The snout projects beyond the small mouth, giving a shark-like profile, and 
the small teeth are mostly uniserial. Gill-slits inferior and converging. The name Sphagebranchus 
was based on a species which evidently belongs to the genus. It has, therefore, clear priority over 
Ichthyapus and Apterichthys. 
This genus is the most simple in structure among the genera of Ophichthyidse, as Ophichthus is 
probably the most specialized. Its loss of fins is doubtless due to degeneration, but it seems nearer 
the primitive type than Brachysomophis or Ophichthus. Only one species obtained in Porto Rico. 
a. Head 6 times in trunk anguiformis 
aa. Head little more than 4 times in trunk. 
b. Color brown, head mottled selacJiops 
bb. Color greenish, without mottlings ophioneus, 16 
16. Sphagebranchus ophioneus Evermann & Marsh, new species. 
Head 4.5 in distance from tip of snout to vent, 12.5 in total length; depth of trunk 48 times in 
total length, depth of head 36 times; distance from tip of snout to vent 2.8 in total length; snout 6 in 
head, mandible 2.5, interorbital 12.7. 
Body cylindrical, tail tapering; longest diameter of head greater than that of body; head forward 
of occipital region long, slender, conic, and sharply pointed; eye minute; mouth inferior, the pointed 
snout far overhanging, tip of lower jaw considerably in front of eye; teeth numerous, directed back- 
ward, conic, sharp, depressible, uniserial in each jaw and on vomer; roof of mouth not entirely covered 
by lower jaw, exposing a triangular space in front of its tip, a single tooth exposed in front on median 
line when the mouth is closed; in the preserved specimen the tooth next behind on each side is also 
exposed, probably due to the contraction of the fleshy tip of lower jaw; a few fleshy papilla; at edge of 
upper lip on each side opposite tip of lower jaw; nostrils not tubular, the anterior on ventral side of 
fleshy tip of snout, the entrance guarded by a pair of fleshy papillae; the posterior in upper lip just 
behind tip of lower jaw which covers nostril when mouth is closed; a row of muciferous pores on each 
ramus of mandible; scattered pores about snout, behind eyes and along upper lip, and a transverse row 
across head at occiput; lateral line distinct, complete, and continuous, commencing on side of head and 
extending to tip of tail, consisting of a slight elevation of the integument, the pores arranged at regular 
