218 ME. C. TATE KEGAN ON THE 



ventral. Caudal obliquely emarginate. Caudal peduncle 3 times as long as deep. 

 Olivaceous, some dark spots on the dorsal ; indistinct light spots on the upper part of 

 the body. 



Total length 300 mm. 



Two specimens (including the type of H. asperatus) : E. Brazil. 



22. Plecostomus wektheimeri. 



Plecostomus wertheimeri Steind. Sitzb. Ak. Wien, lv. 1867, p. 701, pi. i. 



Pseudancistrus wertheimeri Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 45, and Occ. Pap. 

 Cal. Ac. i. 1890, p. 436. 



Depth of body 4f times in the total length, length of head 3f times. Head 

 1^ times as long as broad and If times as long as deep. Diameter of eye %\ times in 

 the length of head, interorbital width 2^, length of snout twice. Length of mandibular 

 ramus 2f times in the interorbital width. Snout obtuse ; upper surface of head 

 nearly flat, without keels or ridges ; operculum and interoperculum with rather 

 short marginal bristles. Scutes not carinate, 23 in a longitudinal series, 8 between 

 dorsal and adipose fin, 11 between anal and caudal. Supraoccipital bordered 

 posteriorly by a pair of scutes. A group of small granular plates behind the temporal 

 plate. 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 well-developed plates on each side of the abdomen. D. I 7, the first 

 ray as long as the head, the last f as long ; length of base of dorsal slightly greater 

 than its distance from adipose fin. Adipose fin small. A. I 5. Pectoral spine 

 extending to base of ventral. Caudal weakly and obliquely emarginate. Caudal 

 peduncle 1\ times as long as deep. Brownish ; some indistinct lighter spots on 

 upper part of body ; dorsal with a dark vertical stripe or series of spots on each 

 interradial membrane. 



Total length 220 mm. 



One specimen : Santa Clara, S.E. Brazil. 



23. Plecostomus Pellegrini, sp. n. 



Depth of body 4 times in the total length, length of head of times. Head a little 

 broader than long and 1^ times as long as deep. Diameter of eye nearly 6 times in 

 the length of head, interorbital width twice, length of snout 2^ times. Length of 

 mandibular ramus 3f times in the interorbital width. Snout short, broad, rounded ; 

 supraorbital edges not raised ; supraoccipital with a low median ridge ; operculum and 

 interoperculum with short marginal bristles. 23 scutes in a longitudinal series, 

 10 between anal and caudal, the anterior and upper scutes with strong but obtuse 

 keels. Supraoccipital bordered posteriorly by a median scute and by one on each 



