220 ME. C. TATE BEGAN ON THE 



median scute from contact with it. Lower surface of head and abdomen naked 

 except for a patch of small granular plates in front of each gill-opening, a strip 

 between the pectorals, and a lateral series of small plates on each side of the 

 abdomen. D. I 7, the first ray f-f the length of head, the last | as long ; length of 

 base of dorsal f the length of head. No trace of an adipose fin. A. I 5. Pectoral 

 spine extending a little beyond base of ventral. Caudal slightly emarginate. Caudal 

 peduncle 2i-2f times as long as deep. Uniformly brownish. 



Total length 300 mm. 



Two specimens : Rio Parahyba. 



26. Plecostomus aspek. 



Rhinelepis aspera Spix, Gen. et Spec. Pise. Bras. p. 4, pi. ii. (1829) ; Cuv. & Val. Hist. Nat. Poiss. 



xv. p. 483 (1840) ; Gunth. Cat. Fish. v. p. 253 (1864). 

 Rinelepis strigosa Cuv. & Val. t. c. p. 480. 



Depth of body 4f times in the total length, length of head 2f times. Depth of head 

 If times in its length, breadth of head 1^ times, diameter of eye 11 times, interorbital 

 width If times, length of snout If times. Length of mandibular ramus 3§ times in 

 the interorbital width. Head flat above, without keels or ridges ; snout obtuse ; 

 opercular plate very large. Scutes spinulose, not carinate, 24 in a longitudinal series, 

 10 between anal and caudal ; a group of small granular plates behind the lower half 

 of the temporal plate and the upper part of the clavicle ; supraoccipital bordered 

 posteriorly by a median scute or pair of scutes and one on each side ; lower surface of 

 head and abdomen completely covered with small granular scales. D. I 7, the first ray 

 equal to f- the length of head and to the length of the base of the fin. Adipose fin 

 represented by a small rounded plate between the eighth and ninth pairs of scutes 

 behind the dorsal. A. I 5. Pectoral spine extending to anterior \ of ventral. Caudal 

 very slightly emarginate. Caudal peduncle twice as long as deep. Colour uniform 

 brownish. 



Total length 330 mm. 



One specimen (type of R. strigosa) : Eastern Brazil. 



2. Hemipsilichthys. 



Xenomystus (non Giinth.) Liitk. Vid. Medd. 1873, no. 13, p. 217. 

 Hemipsilichthys Eigenm. & Eigenm. Proc. Cal. Ae. (2) ii. 1889, p. 46. 



Similar in most characters to Plecostomus, but the snout with a naked margin, the 

 dorsal fin originating above the ventrals, separated from the supraoccipital by 5 scutes, 

 and the teeth in the jaws forming curved crescent-shaped series. 



S.E. Brazil. 



