122 Annals of the Carnegie Museum. 



Eye 4 in the head ; lat. I.23 vittatus. 



cc. Fins, aside from the basal caudal spot, plain ; lateral band a weak line 



on lateral line ; lat. 1.21 vestitus. 



bb. Middle caudal rays not black; D.I, 7; Lat. 1. 23-25 affinis. 



aa. Sides spotted ; D.I, 7; A.I, 5; lat. I.25. 



J. Six spots along lateral line ; a series of corresponding spots along the back ; 

 dorsal and caudal spotted. Eye 4 ; lower lip thin and entirely naked. 



ftexilis. 



dd. Two large spots along the lateral line ; a series of corresponding dorsal 



spots; caudal with 3 vertical dusky bars, sometimes spots. Eye 4.25 ; 



lower lip coarsely tubercular .fimbiintus. 



30. Plecostomus plecostomus (Linnaeus). 



Three specimens, Corumba (340). These specimens with several 

 sent in the first collection which were not recorded from Ascuncion ; 

 Rincomeda on Rio Apa, Arroyo Trementina give us a range of speci- 

 mens from 60 to 390 mm. in length. There is a great modification 

 in the shape of the head. It becomes lower, broader, and very much 

 more rounded with age. The caudal, which is cross banded in the 

 young, becomes spotted. The dorsal which has a single series of 

 spots between the rays comes to have two series. It is evident from 

 the series that Plecostomus bouleugeri is but the young of Plecostomus 

 plecostomus, as Regan has recently stated. 



31. Plecostomus johni Steindachner. 



I am inclined to think that both Plecostomus commersoni and ver- 

 micularis mentioned in the first paper on Paraguayan fishes and Ple- 

 costomus temetzi Boulenger should be placed here. The vermicularis 

 is a small specimen and its identification must be more or less of a 

 guess. 



Our largest specimen is about 200 mm. long. In this the region 

 in front of the gill slit, a band across the breast and a large triangular 

 patch on the middle of the belly are granular and there is a series of 

 larger plates along the sides of the belly between the pectorals and 

 ventrals. Otherwise the lower surface is naked. In the smaller 

 specimen there is also a median granular band between the ventrals. 

 In the shape of the head, spines of the lateral plates, lateral line, etc., 

 the specimens agree with. Plecostomus temetzi. Our larger one differs 

 in having the dorsal with large spots, but these spots are quite obscure. 

 In the smaller specimen the dorsal is uniform dark, as in the type of 

 temetzi. 



32. Xenocara gymnorhynchus Kner. 



One specimen, mountain brook at Sapucay, Central Paraguay (452), 



