FEOM THE EIO JUEUA. 427 



CLUPE1D.E. 



41. Cetengraulis juruensis, sp. n. (Plate XLT. fig. 3.) 



Depth of body 5 times in total length, length of head 3^ times. Snout very strongly 

 projecting, a little shorter than diameter of eye, which is 5| times in length of head 

 and 1^ in interorbital width ; jaws toothless ; maxillary extending to articulation 

 of mandible ; cleft of mouth nearly ^ length of head. Gill-rakers long, finely denti- 

 culate, about 40 on lower part of anterior arch. Dorsal 13, originating at equal 

 distance from end of the snout and base of caudal. Pectoral a little more than ^ 

 length of head, extending a little beyond base of ventral. Anal 23, originating below 

 posterior rays of dorsal. Caudal peduncle twice as long as deep. Caudal deeply 

 forked. Scales 38 in a longitudinal series, 10 in a transverse series. Olive above, 

 silvery on the sides and below ; snout blackish above ; fins pale orange, caudal rays 

 blackish at the end. 



Total length 140 millim. 



A single specimen. 



This fish, the first freshwater representative of the genus Cetengraulis, is nearest 

 to C. edentulus Cuv., which differs in the deeper body. 



42. Pristigaster catanus Cuv. 



OSTEOGLOSSID^. 



43. Arapaima gigas Cuv. 



Dr. Bach has shown me the photograph of a large specimen taken by him. 



GYMNOTID^. 



44. Sternarchus nattereri Stdr. 



45. Sternarchus m.4.crolepis Stdr. 



46. Sternarchus oxyrhynchus M. & T. 



47. Sternarchus tamandua, sp. n. (Plate XLII.) 



Snout produced into a long, nearly straight tube, the length of which equals 4 times 

 its least depth ; mouth very small, with several rows of minute teeth ; eye extremely 

 minute, a little nearer the opercular cleft than the end of the snout. Depth of body 

 half length of head. A very strongly developed adipose fin runs along the whole 

 length of the body, from which it is easily detached. Pectoral ^ length of head. 

 Vent under the chin. Anal 220, originating a little in advance of gill-opening, longest 

 rays rather more than \ depth of body. Scales very small, larger on the upper half of the 

 body than on the lower ; lat. 1. 85. The tail, in the unique specimen, has been injured 

 during life, and bears a short, regenerated caudal fin. Uniform yellowish white. 



Total length 400 millim. 



