-^ 424 ^ 



The latter are intermediate tcwards Plecostomus 

 jyunctatus. with keels of scutes very weaic posteriorly, 

 and in one specimen the dorsal base only just equal 

 its distance from the adipose. 



Three small specimens 2x102— inches in 

 length from the State of São Paulo have scutes very 

 weakly keeled but the length of dorsal case as in 

 P. CGmnwrsonii. These have the tins strongly 

 banded with dark. 



Plecoslomiis lacertii, new species. 



The type No. 7.151, American Museum of Na- 

 tural History, is from Poço Grande ( State of São 

 Paulo), Rio Juquiá, Jan. 1898. It is 67 mm., in 

 length to base of caudal ; head 3.5 in that measure ^ 

 depth 7,0 ; eye 8.0 in head ; snout 2.0 ; depth 

 of head 2.5 in its length ; breadth of head J .6 ; in- 

 terorbital 2.6; pectoral fin 1.6; ventral fin. 1.8; 

 height of anal 2.3; first dorsal ray 1.5; lower 

 caudal lobe 1.3; adipose spine 4.0; mandibular ra- 

 mus 2.5 in interorbital ; barbel minute. Dorsal with 

 8 rays, its base less than its distance from the 

 adipose ; top of the head fiat ; orbital rim slightly 

 raised; mid-line of snout somewhat angulated; scu- 

 tes behind supraoccipital irregular, a]30ut 5 in con- 

 tact with it ; 28 scutes in a longitudinal series ; no 

 keels ; lower surfaces scaleless. Dorsal, ventrals 

 and anal more or less blackish tOAvards their tips ; 

 caudal blackish, especially on the distal portion on 

 the lower lobe ; a somewhat circular colorless area 

 in the center of the upper lobe ; pectorals barely 

 reaching ventrals ; caudal slightly emarginate. 



Three additional specimens, 55 to 70 mm., in 

 length, all from the State of São Paulo, agree with 

 the type in essentials. In two of them the orbi- 

 tal rim is not raised. They have the upper surface 

 and fins irregularly marked with dusky. The 

 species is characterized by the small irregular scales 

 behind the supraoccipital, rather narrow, iiat-topped. 

 head, minute barbel, etc. 



