92 



inch. Hues 



Length of the head (to the front-edge of the tympanum) 0 8^ 



Breadth of the head 0 6£ 



Length of the trunk (to the anus) 2 4 



of the tail .... 4 0 



of the humerus 0 6 



of the fore-arm 0 4| 



of the fourth finger 0 6£ 



of the first finger 0 2 \ 



— — of the entire fore extremity 1 4 



of the femur 0 7 



of the lower leg 0 6i 



-of the foot 0 3± 



- of the fourth toe 0 7i 



of the fifth toe 0 6 



— of the first toe , 0 3 



of the entire hinder extremity 2 1 



Entire length 7 0 



Arges brachycephalus, n. sp. (Siluridce). 



The length of the head is one-fifth of the total length ; the eyes 

 are situated nearly in the middle of the length of the head ; the 

 nostrils are much nearer the extremity of the snout than to the orbit ; 

 ventral fins inserted just below the extremity of the pectoral, on the 

 same level with the dorsal. Brown, dotted with black. Length 7". 



In other respects the specimens agree with the description given by 

 Valenciennes of Arges sabalo ; but those differences in the form, as 

 stated above, are fully sufficient to distinguish the species. There 

 were four specimens, besides several young ones, in Mr. Eraser's col- 

 lection, the acquisition of which appears the more desirable, as one 

 specimen only of the other species is known to exist in European 

 collections. 



Leporinus mulleri, n. sp. (Characini, Mull.). 



B. 4. D. 11. A. 14. L. lat. 39. L. transv. 5/3. 



The height of the body is contained 3| in the total length ; the 

 length of the head 4| ; the diameter of the eye is rather longer than 

 one-fourth of the length of the head, and equal to the length of the 

 snout. The pectoral fins are not quite as long as the head, and reach 

 to the root of the ventrals ; these are inserted just below the front 

 end of the dorsal. Back brownish ; sides lighter ; a blackish band 

 from a deep-black spot on the shoulder to the root of caudal-fin. 



Teeth. — Those in the upper jaw are molar teeth, partly bluntly 

 conical, with a brown top ; others have lost their point, and appear 

 rounded. They may be considered to be arranged in three series ; in 

 the front series are two teeth only, the strongest, one on the left side, 

 and one on the right ; the second series is interrupted in the middle, 

 each half being composed of four teeth ; one tooth (the second) 

 stands a little more out of the row, towards the front ; the third 

 series is the most complete, is curved, extending on the maxillary, 



