THE SHORE FISHES OF PERU 351 



pharyngeals large, usually forming a more or less definite quadrangle; 

 scales large, cycloid, about 23 to 26 in a lateral series; dorsal fin con- 

 tinuous, usually with 9 spines and 10 soft rays, the spines often weak 

 and flexible; anal with 3 spines and usually with 9 soft rays; ventral 

 fins thoracic. 



KEY TO THE GENERA 



a. Teeth in jaws fully coalesced, forming a continuous cutting edge; gill mem- 

 branes narrowly united or separate Scarus (p. 351) 



aa. Teeth in jaws not fully coalesced,. the cutting edge irregular, formed by in- 

 dividual teeth; gill membranes broadly united Xenoscarus (p. 354) 



Genus SCARUS Forskal, 1775 



Body elongate, compressed, moderately robust; head rather short 

 and blunt; mouth moderate or small, lower jaw included; upper lip 

 laterally double, usually becoming narrow or disappearing anteriorly; 

 teeth in the jaws fully coalesced, forming a continuous cutting edge, 

 with an evident median suture, with or without free lateral canines; 

 lower pharyngeals generally considerably longer than broad, concave; 

 upper pharyngeals separate, with a large and a small row of teeth; 

 gill membranes scarcely united to the isthmus; lateral line interrupted 

 posteriorly, commencing again lower down on middle of side, the 

 pores usually branched; dorsal with 9 flexible spines, and about 10 

 soft rays; anal with 3 flexible spines and about 9 soft rays. 



A single apparently new species is included in the collections 

 studied. 



SCARUS DUBIUS. new species 

 FiGtJRE 72 



Head 3.0 to 3.25; depth 3.0 to 3.3; D. IX, 10; A. Ill, 9; P. 14; 



scales 24 or 25; vertebrae 24 (one specimen dissected). 



Body moderately compressed, its greatest thickness about half 

 its depth; dorsal outline gently depressed over nostrils, elsewhere 

 convex; caudal peduncle rather long, compressed, 1.9 to 2.3 in head; 

 snout moderately long, 2.9 to 3.4; eye small, placed high, 3.9 to 4.3; 

 interorbital rather broad, only gently convex in cross section, 3.1 to 

 3.4; mouth small, placed below level of lower margin of eye, nearly 

 terminal, with the lower jaw only slightly included; upper lips double 

 throughout (the inner one becoming narrow anteriorly in the largest 

 specimen in the collection) ; maxillary hidden under skin of preorbital, 

 faiUng to reach vertical from anterior margin of eye, 4.2 to 4.75 in 

 head; teeth in jaws white, quite fully coalesced, the cutting edges 

 scarcely indented, without canines; lower pharyngeal plate scarcely 

 longer than broad, more or less oval in shape, though slightly reduced 

 in width and somewhat angulate anteriorly, its surface distinctly 



