REVIEW OF OPHIDIOID FISH GENUS OLIGOPUS — COHEN 7 



Misidentifications: Pteridium atrum Emery, 1885, p. 158, fig. 21 (30 mm. specimen, 

 description, probably Benthocometes robustus). — Roule and Angel, 1930, 

 p. 110, pi. 6, fig. 146 (Azores, description of postlarvae). 



Study materials. — 1 specimen, Nice, MCZ 26457. 



Counts and measurements.— (Measurements given in mm., 

 followed by percent of standard length in parentheses) D 74; A 52; 

 pectoral 19; vertebrae 40; caudal 10; vertical scale rows about 83; 

 SL 89; body depth at dorsal origin 17.5 (19.7); predorsal 31.2 (35.0); 

 preanal 50.0 (56.1) ;HL 25.0 (28.0); snout 5.8 (6.5); orbit 3.0 (3.4); 

 upper jaw 14.2 (15.9); greatest maxillary width 4.5 (5.1); greatest 

 head width 11.0 (12.3). (See D'Ancona, 1938, p. 162, for additional 

 data.) 



Description. — Squamation: Scales present on large area on top of 

 head behind eye level; present on side of head on opercle and in area 

 ahead of opercle extending forward nearly to eye and ventrally to 

 region behind maxillary. Dorsal and lateral scale patches separated 

 by scaleless lateral canal. 



Lateralis system: Lateral canal with single pore near upper angle of 

 opercle. Supraorbital canal with 2 pores: 1 in front of, and below, 

 anterior nostril; the other, difficult to find, above anterior nostril. 

 Infraorbital canal with 6 pores: 3 beneath nostrils in skinfold over 

 upper jaw; 1 very small pore close to level of posterior part of eye; 2 

 larger pores above posterior expanded part of maxillary. Preoper- 

 culomandibular canal with 8 pores: 2 at tip of dentary, 1 opening 

 anteriorly, the other posteriorly; 1 beneath lower lip at about midlength 

 of snout; 1 at about midlength of jaw; 1 shghtly ahead of posterior 

 margin of maxiUary; 1 slightly behind same; 2 on posterior margin of 

 preopercle. 



Circumorbital and interorbital areas and side of snout cavernous, 

 covered with thick skin bearing scattered papillae. Interorbital area 

 particularly rugose. 



Lateral line marked by small, dark, dermal filaments. Series of 23 

 originates above opercle. Between opercle and level of dorsal fin 

 origin filaments in elongate, irregular cluster from which lateral line 

 extending posteriorly in straight line, between midline and dorsal 

 profile. Dorsal line terminating 63 mm. from tip of snout. Second 

 line of about 40 filaments originating in midline close to level of pos- 

 terior tip of pectoral fin, descending, then rising to midline of body to 

 form shallow irregular semicircle with lowest point opposite vent, 

 then extending straight back in midline of body to tail. Filaments 

 similar to those along lateral lines scattered about on head. 



Dentition: Premaxillary with band of uniform granular teeth. 

 Dentaries with similar teeth and irregular row of larger, conical 

 teeth along inner edge of granular band. Head of vomer a broad 



