182 PROCEEDINGS OF THE NATIONAL MUSEUM vol.94 



96. Branched caudal fin rays usually 15, rarely 14 or 16; branched anal 

 rays 20 to 29; skin naked; body excessively streamlined; teeth 

 villiform to incisor on jaws and vomer; gill membranes joined to 

 isthmus, or gill openings sometimes restricted to in front of 

 pectoral base; eyes nearly concealed in skin, margins fused; 

 opercle well developed; pelvics inserted under last dorsal ray 



or behind dorsal base; dorsal rays i, 6 Cetopsidae (p. 250) 



86. Dorsal fin posteriorly on body, usually in posterior half of standard 

 length; anal also far back; opercle and interopercle spinous; no 

 mental barbels; usually twin barbels at each corner of mouth; nasal 

 barbels present or absent; pelvics inserted under or in front of 

 dorsal fin; branched caudal fin rays usually 10 to 12. 



Pygidiidae (p. 256) 

 36. Body covered with bony plates or at least a series along lateral line posteri- 

 orly, these with backward-projecting spines. 

 10a. A series of bony plates along midsidcs, theee with a backward-directed 

 ' spine, at least posteriorly; a pair of maxillary and 2 pairs of mental 



barbels present; barbels sometimes branched or fimbriated; gill 

 membranes united with isthmus; air bladder much specialized; 

 adipose fin present, short, base usually somewhat restricted; branched 

 caudal fin rays usually 15; dorsal rays I, 4 to I, 6; anal rays about 10 

 to 16; dorsal and pectoral spines strong, with a locking mechanism; 

 humeral process present; pectoral spine serrated-Doradidae (p. 269) 

 106. Two longitudinal rows of plates completely covering sides of body; 

 twin barbels at each rictus or corners of mouth; teeth villiform; gill 

 membranes broadly joined to isthmus; nostrils not together but only 

 a little distance apart; eyes superior or lateral; adipose, if present, 

 represented by a spiny projection and membrane; branched caudal 

 fin rays usually 12, occasionally 11; dorsal rays 7 to 12. 



Callichthyidae (p. 275) 



16. Mouth inferior; lower lip reverted, forming with upper lip a disklike mouth; 



gill membranes broadly united with isthmus; nasal openings close together; 



no mental barbels; maxillary barbel more or less joining with lips to form 



disklike mouth; adipose fin, if present, represented by a bony projection 



and a membrane. 



11 o. Body naked, with plates; teeth bicuspid, in a narrow band on each jaw; 



pelvics inserted under dorsal base; branched caudal fin rays usually 



11 Astroblepidae (p. 278) 



116. Body completely covered with bony plates, in rows; teeth erect, with 

 bilobed or spoon-shaped tips, on jaws, none on vomer or palatines; 

 premaxillary elements separated at midline each with a single series of active 

 teeth, dentary similar; branched caudal fin rays usually about 10 or 

 about 14; intestinal canal coiled upon itself; air bladder minute. 



Loricariidae (p. 285) 



Family BAGREIDAE 



This family includes the marine catfishes, with representatives in 

 brackish waters. They are naked forms, with a pair of maxillary 

 barbels and one or two pairs of mental barbels, but differ from other 

 related forms in having the anterior and posterior nasal openings close 

 together, with the rear nasal opening covered with a valve; insertion 

 of pelvic fins behind base of dorsal fin ; adipose fin base shorter than 



