670 ON NEW SOUTH-AMERICAN FISHES. 



10. Arges cirratus, sp. n. 



Length of head 3|^ in the length of the fish. Interocular width 

 rather more than distance from eye to posterior nostril, rather 

 less than | the length of head. Nasal flap produced into a harbel 

 which is as long as the diameter of the eye ; maxillary barbel not 

 quite reaching gill-opening ; teeth of outer series of prfemaxil- 

 laries unicuspid, acute ; mandibulary teeth bicuspid. First dorsal 

 ray ^ the length of head ; pectoral extending to base of ventral ; 

 ventrals inserted below anterior part of dorsal, nearly reaching 

 anal. Spine of adipose fin well developed, movable, connected 

 by a membi-ane with the caudal peduncle, inserted at a distance 

 from caudal equal to about | the length of the middle rays of 

 that fin. Distance from tip of snout to origin of dorsal fin 2|- 

 in the length of the fish, from base of last anal ray to caudal 5f . 

 A few large dark spots on body; a blackish bar across middle of 

 caudal fin. 



A single specimen, 24 mm. in total length, from the Rio 

 Condoto, Eio San Juan, S.W. Colombia, collected by Mr. G. 

 Palmer. 



EXPLANATION OF THE PLATES. 



Plate LXXV. 



Fig. 1. Chcetostomus lepturus. 

 Fig-. 2. „ paucispinis. 



Fig. 3. „ pahueri. 



Plate LXXVI. 



Fig. 1. JTenocai'a multispims. 

 Fig. 2. „ heterorhynchus. 



Fig. 3. Flecostomus Jiondce. 



Plate LXXVII. 



Fig. 1. Oxyloricaria tamana (X|). 

 Figs. 1 a, 1 h. Heads of ^ & ? . 

 Fig. 2. O. leightoni. 

 Fig. 3. Otocinclus maeulipinnis (X2). 



