FISHES OF THE FAMILY LOKICARIIME. 311 



ray 2^-2§ times in the total length, from base of last anal ray to the caudal 

 5f— 6-y times. Body spotted or marbled with blackish ; dorsal and caudal with some 

 dark spots on the rays. 



Total length 85 mm. 



Eight specimens from Colombia. 



4. Arges cyclopum. 



Pimeloclus cyclopum Humboldt^ Obs. Zool. i. p. 21, pi. vi. (1805). 

 Cyclopium humboldtii Swainson, Nat. Hist. Fish. ii. p. 305 (1839). 

 Arges cyclopum Cuv. & Val. Hist. Nat. Poiss. xv. p. 340 (1840). 

 ^tygogenes humboldtii Giiuth. Cat. Fish. v. p. 223 (1864). 

 Stygogenes cyclopum Gunth. t. c. p. 224. 



Length of head nearly 4 times in the total length. Interocular width equal to the 

 distance from eye to posterior nostril, 3-j times in the length of head. Teeth of the 

 outer series of the praemaxillaries mostly unicuspid ; mandibulary teeth bicuspid ; 

 barbel extending to gill-opening. First dorsal ray equal to ^ the length of head ; 

 pectoral spine extending to middle of ventral ; ventrals originating below the first 

 dorsal ray, extending to the anal opening. Spine of adipose fin fairly well developed, 

 freely movable, inserted at a distance from the caudal equal to f the length of the 

 middle rays of that fin. Adipose fin represented by a membrane connecting the spine 

 posteriorly to the caudal peduncle. Distance from tip of snout to base of first dorsal 

 ray 2^-2f times in the total length, from base of last anal ray to caudal 4§ times. 

 Body spotted or marbled with dark brown ; caudal dark at the base and in its 

 posterior half. 



Total length 45 mm. 



Four specimens from Madame Ida Pfeiffer's collection, locality unknown, agree fairly 

 well with Humboldt's figure and may be provisionally referred to this species, which 

 certainly belongs to the section with short adipose fin and movable spine. 



A. cyclopum was originally recorded from the Andes above Quito, Ecuador. 



5. Arges whymperi. 



Arges whymperi (part.) Bouleng. Proc. Zool. Soc. 1890, p. 451, pi. xli. fig. 2. 



Length of head 4f times in the total length. Interocular width nearly equal to the 

 distance from eye to posterior nostril, 3f times in the length of head. Teeth of the 

 outer series of the praemaxillaries mostly unicuspid ; mandibulary teeth bicuspid ; 

 barbel extending f- of the distance from its base to the gill-opening. First dorsal ray 

 equal to f the length of head ; pectoral spine extending to anterior ^ of ventral ; 

 ventrals originating nearly below the first dorsal ray, extending f of the distance from 

 their base to the anal opening, which is situated at ^ of the distance from the base of 



vol. xvn. — part in. No. 16. — October, 1904. 2 t 



