SOUTH AMERICAN NEMATOGNATHI. 149 



gill-opening than to snout. Interorbital slightly wider than 

 the diameter of the eye. Humeral process indistinctly striate. 

 Dorsal higher than long, the length of its base equals its dis- 

 tance from the head. Adipose 3| in body. Caudal deeply 

 forked, the lobes pointed, upper lobe longer than head. Pec- 

 toral extending to below middle of dorsal, its spine stout, 

 compressed, its posterior margin spiny. Uniform grayish" 

 above, white below; dorsal and caudal fins minutely dotted 

 with black. Head 4f; depth 5; Br. 6; D. I, 6; A. 11. (Giinther.) 



elongatus 113. 

 gg. Snout not produced. 



h. Pectoral spine strong, compressed, with from 10-15 recurved 

 hooks behind, the length of the hooks equals, or almost 

 equals, the width of the spine. 



i. Head conical or subconical. lateristriga 114. 



ii. Head depressed, the sides slanting outwards, snout and 

 postorbital portion of head slightly convex in cross-sec- 

 tion; the occipital process scarcely reaching the basal bone 

 of the dorsal spine. Eye nearer opercular margin than to 

 snout. (Steindachner.) harttii 115. 



hh. Pectoral spine curved, flattened, comparatively slender; 

 its posterior margin "smooth" or with teeth which are not 

 more than or the width of the spine, recurved notches 

 near its tip in front. Maxillary barbel extending to the sec- 

 ond fourth of the adipose dorsal. buckleyi 116. 

 fff. A dark band along the sides, continued forward on head; teeth 

 of pectoral spine one-half the width of the spine. 

 j. Eye 4 in head; lateral band continued on head but not on 

 caudal; pectoral spine slender, much as in buckleyi, but the 

 teeth stronger. vittata 117. 

 jj. Eye 3-J-3f in head, lateral band continued on head, and 011 

 the middle rays of the caudal; pectoral spine very broad, de- 

 pressed, almost straight. chagresi 118. 

 dd. Dorsal rays I, 7; pectoral fin extending to the ventral fins, which 

 reach to the anal; head flat; eye median; distance between the 

 angles of the mouth 2| in head. Maxillary barbels extending beyond 

 origin of adipose dorsal; postmental barbels not to middle of pecto- 

 ral. First dorsal ray slightly longer than head; dorsal spine shorter 

 than the head; distance between dorsal and adipose fin longer than 

 the base of the former; adipose dorsal 3| in the length. Upper lobe 

 of caudal 1 times as long as head. Posterior serration of pectoral 

 much weaker than in gracilis. Reddish-brown; a dark brown hume- 

 ral spot; a narrow dark bar along the lateral line. Head 4|; depth 

 5. D. I, 7; A. 12. (Steindacher.) brasiliensis 119. 



