38 FISHES FROM BRAZIL 



lateral plates; 3 between the occipital and dorsal spine, the last very narrow 

 medially ; 7 between the dorsals ; 4 between the adipose dorsal spine and the 

 caudal; 12 between the anal and the caudal. The cross lines on the belly 

 divide the granulations into much larger plates than in P. plecostomus, and 

 there is a larger naked area at the bases of the ventral fins. 



Dark spots cover the body, on the ventral as well as the dorsal surface, 

 and the fins. Each dorsal membrane bears two rows of them. 



This species is most closely related to P. plecostomus, but differs in 

 having a smaller eye, the occipital and temporal ridges scarcely developed, 

 the dorsal fin overlapping the adipose dorsal, the plates on the belly coarser, 

 the spinules on the lateral scales coarser, and the whole posterior part of 

 the body shorter, so that the anal and ventrals and vent are more posteriorly 

 placed in relation to the caudal base. 



Numerous specimens from 2 to 8 inches in length were collected in the 

 little disconnected ponds and in the muddy stream at Ceara Mirim, the boys 

 catching them under the overhanging grassy banks in their hands and in 

 dip-nets. The type is 8 inches in entire length. {Pusarum, named in 

 memory of the boys to whom I owe the collection of fishes at Ceara Mirim — 

 the best collectors we found in Brazil.) 



113. Plecostomus plecostomus (Linnaeus). 



Three specimens were taken at Para, the largest 8 inches in length. 

 This species resembles Plesoctomus verres very closely. It differs not only 

 in having the supraoccipital bounded behind by a single plate, but the dorsal 

 is less angulated, less oblique and straight on its posterior edge, and its 

 outline more rounded. The scales on the breast and belly are more segre- 

 gated into little square areas formed by diagonal cross lines. 



114. Plecostomus verres (Cuvier and Valenciennes). 



Several specimens were collected at Para, the largest a foot in length. 

 They agree very well with current descriptions except that "scutes carinate 

 except on caudal peduncle" (Regan Trans. Zool. Soc. Lond. XVII, p. 209) 

 does not adequately describe these, for the scales on the caudal peduncle 

 have low keels, not so sharp and high as they are anteriorly, but still very 

 evident. 



115. Acanthicus hystrix Spix. 



A specimen of this rare species, 14 inches long without the caudal 

 filaments, was collected in the market at Para. It has 8 soft rays in the 

 dorsal. The barbels, unlike the specimen described by Dr. Eigenmann, 

 scarcely reach as far posteriorly as the edge of the lower lip. 



