1911.] 



NATURAL SCIENCES OF PHILADELPHIA. 



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slight median pre ventral ridge or keel. Postventral region rather 

 constricted. Caudal peduncle well compressed, its least depth 

 about 1^ its length. 



Head well compressed, flattened sides slightly constricted below, 

 upper and lower surfaces rather evenly convex, profiles similarly 

 inclined and slightly convex anteriorly. Snout a little convex in 

 profile, surface well convex, length about f its basal width. Eye a 

 trifle ellipsoid, rather high, its centre about first third in head. 

 Eyelid narrow and thin. Pupil vertically ellipsoid. Maxillary well 

 inclined, extends till below front pupil edge, and distally expanded 

 till about 3^ in eye. Jaws strong, firm, equal. Upper lip tough, 

 firm, moderate. Lower lip thick, free in front, and rather fleshy. 



Fig. 3. — Brycon scapidaris Fowler. Type. 



Mouth moderate, commissure rather short, horizontal. Premaxillary 

 teeth triserial, mostly with an enlarged median denticle and a rather 

 obtuse small denticle or cusp each side basally, former much in 

 contrast with latter. Posterior premaxillary teeth similar, only 

 broader and a little larger. All premaxillary teeth rather thick, 

 with entire edges, surfaces convex, strong and firm. Maxillary 

 with a series of rather small close-set conic short teeth over about 

 first or upper § of its lower edge, these also all more or less concealed 

 by membrane over bone. Mandibular teeth uniserial, first 3 each 

 side of symphysis enlarged, largest of all teeth, and laterally on each 

 mandibular ramus those following quickly decreasing in size, and 

 some becoming minute, so that dentition does not extend more than 



