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 
confluent 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 Paranda. 
IX. STERNARCHORHYNCHUS Castelnau. 
Sternarchorhynchus CASTELNAU, Anim. Am. Sud. Poiss., 1856. 
Rhamphosternarchus GUNTHER, Cat., VIII, 4, 1870 (oryrhynchus). 
Type, Sternarchorhynchus miilleri 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 sealed at the base. 
13. Sternarchorhynchus oxyrhynchus (Miiller and Troschel). 
Sternarchus oxyrhynchus Mt.tupr AnD TroscuHe., Hore Ichthyol., III, 16, pl. I, 
figs. 1 and 2, 1849 (Essequibo); Kaup, Apod., 127, 1856; GitnrueEr, Cat., 
VII, 4, 1870 (British Guiana); BouLENncER, Trans. Zoél. Soc., XIV, 427, 
1898 (Rio Jurua). 
Sternarchorhynchus oayrhynchus EIGENMANN AND HIGENMANN, Proc. U. 8. Nat. 
Mus., XIV, 1891, 62; ErgzENMANN AND Warp, Proc. Wash. Acad. Sci., VII, 
1905, 167 (Guiana and Rio Jurua); von InERING, Os Peixes do Brazil, Part 
1 A, 1907; ErtaenMANN, Repts. Princeton Univ. Exp. Patagonia, III, 1910 
(Guiana). 
