140 MEMOIRS OF THE CARNEGIE MUSEUM. 



depth of the head in the occipital region 1.2 to 1.4 in the greatest depth of the 

 body; anus on or a little behind the vertical from the posterior margin of the eye; 

 dorsal and ventral profiles tapering very slightly and almost straight. Snout 

 produced, straight and tubular (the length varies with the size, the largest having 

 the longest snout, hence the range of the measurements in which the head and 

 snout figure). Mouth small, inferior; gape short, from 5 to 8 in snout; jaws almost 

 equal but lower included by the hood-like upper, so that the opened mouth appears 

 under the upper jaw; teeth wanting. 



Caudal peduncle 3.5 to 4.5 in the total length; pectorals 1.8 to 2.8 in the head; 

 origin of anal on or very slightly behind, the vertical from the origin of the pectorals. 



Ground-color buff; snout and top of head more or less completely covered 

 with black, especially, the distal half of the snout; a number of irregular black 

 blotches down the middle of the back, and a second row of black spots more or less 

 confiuent with the dorsal ones in the region of the lateral line; caudal appendage 

 completely encircled by two or three black bands (all the black markings vary 

 with the size of the fish, smallest specimens being almost without markings). 

 Fins hyaline. 



Distribution: Guiana, Lower Amazon, and Parana. 



TX. Sternarchorhynchus Castelnau. 



Sternarchorhynchus Castelnau, Anim. Am. Sud. Poiss., 1856. 

 Rhmnphosternarchus Gunther, Cat., VIII, 4, 1870 (oxyrhynchus) . 



Type, Sternarchorhynchus millleri Castelnau. 



With fontanels; a caudal fin; snout produced, decurved; size rather small, not 

 exceeding 300 mm. in length; body compressed and slightly elongate, very slender 

 in caudal region; head medium, conical, and produced; gape very small; teeth in 

 both jaws; eyes small and covered by a membrane. Scales cycloid; lateral line 

 complete; origin of anal distinctly in front of the vertical from origin of the pec- 

 torals; anal long, widest near the middle of the body and narrowing near both head 

 and tail; caudal fin small, terminal, and fan-shaped, slightly scaled at the base. 



13. Sternarchorhynchus oxyrhynchus (Mliller and Troschel). 



Sternarchus oxyrhynchus MUller and Troschel, Horae Ichthyol., Ill, 16, pi. II, 

 figs. 1 and 2, 1849 (Essequibo); Kaup, Apod., 127, 1856; GDnther, Cat., 

 VIII, 4, 1870 (British Guiana); Boulenger, Trans. Zool. Soc, XIV, 427, 

 1898 (Rio Jurua). 



Sternarchorhynchus oxyrhynchus Eigenmann and Eigenmann, Proc. U. S. Nat. 

 Mus., XIV, 1891, 62; Eigenmann and Ward, Proc. Wash. Acad. Sci., VII, 

 1905, 167 (Guiana and Rio Jurua); von Ihering, Os Peixes do Brazil, Part 

 1 A, 1907; Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910 

 (Guiana). 



