242 ME, C. TATE BEGAN ON THE 



4. Panaque. 



Cochliodon (non Cochlodon D'Orbigny) Kner, Denkschr. Ak. Wien, vii. 1854, p. 265 ; Eigenm. & 



Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 44, and Occ. Pap. Cal. Ac. i. 1890, p. 424. 

 Panaque Eigenm. & Eigenm. 1. c. and t. c. p. 425. 



This genus is distinguished from Ancistrus by the teeth, which are few in number 

 and spoon-shaped. D. 17. A. I 4. 



Magdalena, Orinoco, Amazon, and La Plata Systems. 



Key to the Species. 



I. Interoperculum not notably spinate LP. cochliodon Kner. 



II. Interoperculum armed with some slender evertible spines. 



A. Supraoecipital nearly flat 2. P. dentex Crthr. 



B. Supraoecipital arched, elevated. 



Diameter of eye 9 times in the length of head, interorbital width twice 



(in specimen of 180 mm.) 3. P. gibbosus Stdr. 



Diameter of eye 7\ times in the length of head, interorbital width 1 § times 



(in specimen of 210 mm.) 4. P. nigrolineatus Ptrs. 



1. Panaque cochliodon. 



Hypostomus cochliodon Kner, Denkschr. Ak. "VVien, vii. 1854, p. 265, pi. ii. fig. 1. 

 Plecostomus cochliodon Gunth. Cat. Fish. v. p. 238 (1864). 



Cochliodon cochliodon Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 44, and Oec. Pap. Cal. Ac. 

 i. 1890, p. 425. 

 Depth of body 4 times in the total length, length of head 3-3 j times. Head be- 

 times as long as broad and If times as long as deep. Diameter of eye 6A-6|- times in 

 the length of head, interorbital width 14— 2f times, length of snout If— If times. Both 

 jaws with 8 or 9 teeth on each side. Snout narrowed anteriorly, supraorbital edges 

 moderately raised ; supraoecipital with median ridge, ending posteriorly in a pointed 

 process ; temporal plates obscurely carinate ; interoperculum scarcely more spinate than 

 the other plates of the head. Scutes spinulose, the anterior carinate, 27 in a longitudinal 

 series, 8 between dorsal and adipose fin, 14-1-5 between anal and caudal. Supra- 

 occipital entirely bordered posteriorly by a single scute. Lower surface of head and 

 abdomen completely covered with small granular scales. D. I 7 ; length of base of 

 dorsal equal to its distance from the middle of the spine of adipose fin. A. I 4. 

 Pectoral spine extending to anterior £ of ventral. Caudal emarginate. Caudal 

 peduncle 3^ times as long as deep. Olivaceous, with some dark spots on head, body, 

 and fins. 



Total length 200 mm. 



Two specimens : Paraguay; R. Jungada, Matto Grosso; Rio Cujaba. 



