388 CALIFORNIA ACADEMY OF SCIENCES. 



Anal fin as high as the snout and the eye. Ventrals 

 short, not reaching the anal. Pectorals reaching beyond 

 middle of ventrals, little lower than the first dorsal ray, 

 the spine strongly spiny on its outer margin, almost 

 smooth on its inner margin. 



Back marbled; sides with numerous minute dark dots; 

 dorsal rays spotted with dark; middle caudal rays black- 

 ish; anal and inner surfaces of ventrals and pectorals 

 spotted like the dorsal fin. 



D. I, 7; A. 6; V. I, 5; P. I, 5; Lat. 1. 26. 



Subfamily HYPOPTOPOMINvE. 

 LXXVI. Hypoptopoma. 



Hypoptopoma Giinther, Proc. Zool. Soc. Lond. 1868, 

 234 (thoracatum). 



This genus is distinguished by its low, spatulate 

 snout, and by the armature of the belly. The eyes are on the 

 lateral edge of the head. In the shape of the body it ap- 

 proaches PI. granlosus. The breast is covered by two 

 pairs of granular plates, the dermal ossification of the 

 clavicula and coracoid. 



Habitat: Amazon from Rio Negro westward; Venezuela. 



ANALYSIS OF THE SPECIES OF HYPOPTOPOMA. 



a. Lateral plates not keeled. 



b. Space between the suborbital shield and the clavicle partially naked; 

 lateral plates with spinj' ridges; caudal with dark bars. 



thoracatum 334. 



bh. Space between the suborbital shield and the clavicle with an osseus 



shield; lateral plates smooth; caudal rays brown, margin of the caudal 



and a vertical line near its base pale; dorsal deep brown at base, dark 



spots on its middle. gulare 335. 



aa. Median lateral plates keeled; pectoral spine more strongly serrate on 



its inner than on its outer margin. carinatu7n 336. 



334. Hypoptopoma thoracatum. 



Hypoptopoma thoracatum Gtinther, Proc. Zool. Soc. Lond. 1868, 

 234, fig. 2 (Xeberos); Peters, MB. Ak. Berl. 1877, 471 (Cala- 

 bozo); Steindachner, Deuk. Ak. Wien, xli, 47, pi. iv, 1879 (Am- 



