462 PROCEEDINGS OF THE ACADEMY OF [Oct., 



similar to those extending whole length of bone. A long series of 

 still finer palatine teeth. Interorbital space broad and a trifle convex. 

 Gill-opening forward opposite anterior nostril. Rakers 8 + 10 

 rudimentary denticles. Filaments f of orbit. Tubes in lateral line 

 simple. Vent shortly before anal fin. Color in alcohol brownish- 

 brassy, back a little darker than rest of body and with some metallic 

 greenish tints. Fins all pale greenish-brown, each one more or less 

 grayish or pale dusky marginally. Base of caudal with a blackish 

 blotch a little less than orbit. Adipose fin brownish. Iris mostly 

 dark brownish, reddish below. Length 8f inches (caudal damaged). 

 Type. 



The others show: Head 3 to 3|; depth 3^ to 4; D. ii, 9; A. v, 20, i to 

 V, 24, i; scales about 80 to 95 in lateral line to base of caudal, and about 

 5 more on latter; snout 3 in head; eye 4^ to 5^; maxillary 1^ to If; 

 interorbital space 3^ to 3f ; least depth of caudal peduncle 4|^ to 4f ; 

 length of body 5f to 8i inches. 



Subgenus ACESTRORHYNCHUS Eigenmann. 



Body elongate, depth 6 or 7. 

 Acestrorhynohus falcirostris (Cuvier). 



XipJwrhamphus falcirostris Cope, Proc. Amer. Philos. Soc. Phila., XVII, 

 1877-78 (May 17, 1878), p. 688. Peruvian Amazon. Prof. J. Orton. 



Head 3^ to 3i; D. ii, 9; A. v, 21, i; width of head 3f to 3f in its 

 length; snout 2\ to 2f ; eye 4f to 5^; maxillary ly to 1^; interorbital 

 space 3f to 5; least depth of caudal peduncle 5; length (caudals dam- 

 aged) 6^ to 11 inches. Two examples from the collections of 1873 

 and 1877. 

 Acestrorhynohus heterolepis (Cope). Fig. 50. 



Xiphorhamphus heterolepis Cope, Proc. Amer. Philos. Soc. Phila., XVII, 

 1877-78 (May 17, 1878), p. 687. Cotypes, Nos. 21,246 (type) to 21,248, 

 A. N. S. P. Peruvian Amazon. Prof. J. Orton. 



Width of head 3|- in its length; interorbital space 3^. Body com- 

 pressed, edges rounded and upper and lower surfaces of caudal peduncle 

 bevelled. Chest with a median keel. Head well compressed. Snout 

 convex above, and its width If in its length. Teeth along edges of 

 jaws uniserial above, 2 canines at tip in front, midway in length of 

 snout a large canine on each side a little inside, and 3 more between 

 it and front of eye becoming larger as they progress back. In man- 

 dible 4 canines at symphysis, all well separated, and second pair 

 largest. Just behind second pair 1 or 2 small teeth, then 3 enlarged 

 canines middle of which is largest, and then follows a single series of 

 small teeth like those along edge of maxillary. A single long series 



