264 ME. C. TATE REGAN ON THE 



clavicles ; abdomen covered by 3 longitudinal series of plates. D. I 7 ; origin of dorsal 

 above that of ventrals, the length of its base equal to its distance from supraoccipital. 

 Adipose fin present. A. I 5. Pectoral spine extending to middle of ventral. Caudal 

 emarginate. Caudal peduncle slightly compressed, 3^ times as long as deep. 

 Olivaceous ; caudal with brownish spots or bars. 



Total length 70 mm. 



Two specimens: Upjjer Amazon. 



2. Hypoptopoma carinatum. 



Hyj>optopoma carinatum Steind. Denkschr. Ak. Wien, xli. 1879, p. 49, pi. iv. fig. 3. 

 Oxyropsis wrightiana Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 39, and Occ. Pap. Cal. 

 Ac. i. 1890, p. 387. 



Depth of body 7-^ times in the total length, length of head 3^ times. Diameter of 

 eye 5^ times in the length of head, interorbital width 2-2^ times. Occipital region 

 evenly convex, without median ridge. Scutes spinulose, 25 in a longitudinal series, 

 those of the middle lateral series with a median keel. Lower surface of head with a 

 naked area in front of clavicles ; abdomen covered by 3 longitudinal series of plates. 

 D. I 7 ; origin of dorsal above that of ventrals, the length of its base a little more than 

 its distance from supraoccipital. No adipose fin. A. I 5. Pectoral spine extending 

 to middle of ventral. Caudal emarginate. Caudal peduncle depressed, broader than 

 deep, its depth about 7 times in its length. Olivaceous, lower lobe of caudal 

 blackish. 



Total length 41 mm. 



One specimen (type of Oxyropsis wriyhtiana) : Upper Amazon. 



3. Hypoptopoma guentheri. (Plate XV. fig. 2.) 

 Hypoptopoma guentheri Bouleng. Proc. Zool. Soc. 1895, p. 526. 



Depth of body 5i-5f times in the total length, length of head nearly 3 times. 

 Diameter of eye 5-6 times in the length of head, interorbital width If times. 

 Occipital region evenly convex, without median ridge. Scutes spinulose, not carinate, 

 22 in a longitudinal series. Lower surface of head with a transverse series of 4 small 

 plates in front of the clavicles ; abdomen covered by 2 longitudinal series of plates, . 

 the third series represented by a single anterior median plate. D. I 7 ; origin of dorsal 

 above that of ventrals, the length of its base equal to its distance from the supra- 

 occipital. No adipose fin. A. I 5. Pectoral spine extending to posterior extremity 

 of ventral. Caudal emarginate. Caudal peduncle slightly compressed, 3^ — 3-^- times as 

 long as deep. Dorsal and caudal with dark spots or bands. 



Total length 65 mm. 



Seven specimens from Descalvados, Matto Grosso, Paraguay System. 



