FISHES OF THE FAMILY LOEICAKILTLE. 207 



surface of head and abdomen, in the adult, almost completely covered with small 

 granular scales. D. I 7, the first ray about as long as the head, the last \- § as long ; 

 length of base of dorsal equal to its distance from posterior part of spine of adipose 

 fin. A. I 4. Pectoral spine extending beyond base of ventral. Caudal moderately 

 emarginate, the outer rays scarcely produced. Caudal peduncle 3-g~4 times as long as 

 deep. Numerous dark spots on head, body, and fins, those on the head the smallest, 

 those on the dorsal in 2-4 series on each interradial membrane, those on the caudal 

 usually indistinct. 



Total length 460 mm. 



Twelve specimens (including the type of the species and a co-type of P. limosus) : 

 Rio La Plata and its tributaries ; Eio Grande do Sul. 



3. Plecostomus punctatus. 



Hypostomus punctatus Cuv. & Val. Hist. Nat. Poiss. xv. p. 493 (1840). 

 Hypostomus subcarinatus Castelu. Auim. Am. Sud, p. 42, pi. xxi. fig. 1 (1855). 

 Plecostomus punctatus Giinth. Cat. Fish. v. p. 233 (1864). 

 Plecostomus affinis Steind. Sitzb. Ak. Wien, lxxiv. 1876, p. 685. 



Plecostomus commersonii Eigenm. & Eigeum. Proc. Cal. Ac. (2) i. 1888, p. 168, and Occ. Pap. Cal. 

 Ac. i. 1890, p. 403. 



Depth of body 5-6 times in the total length, length of head about 3 J times. Depth 

 of head lf-lf times in its length, breadth of head 1^-lJ times, diameter of eye 

 6-8-| times, interorbital width 2f-2f times, length of snout If times. Length of 

 mandibular ramus 2f-3 times in the interorbital width. Snout ovate, more or less 

 narrowed anteriorly ; supraorbital edges not raised ; supraoccipital with low median 

 ridge; temporal plates not carinate. Scutes spinulose, the anterior carinate, 28-30 in 

 a longitudinal series, 9 between dorsal and adipose fin, 14-16 between anal and caudal. 

 Supraoccipital entirely bordered posteriorly by a single scute. Lower surface of head 

 and abdomen, in the adult, almost completely covered with small granular scales. 

 D. I 7, the first ray as long as or a little longer than the head, the last §-§ as long; 

 length of base of dorsal nearly equal to its distance from the adipose fin. A. I 4. 

 Pectoral spine extending to anterior \ of ventral. Caudal emarginate. Caudal 

 peduncle 3|-4f times as long as deep. Numerous small dark spots on head, 

 body, and fins, those on the dorsal (in the adult) in 2 series on each interradial 

 membrane. 



Total length 300 mm. 



Twelve specimens (including the types of the species and of //. subcarinatus) : 

 Southern and Eastern Brazil. 



Under the names P. commersonii affinis and P. commersonii scalriceps, Eigenmann 

 distinguishes two varieties of this species, which are said to have larger spots than the 

 typical P. punctatus, the second also having a large naked area on the head behind the 



vol. xvn. — part in. No. 3. — October, 1904. 2 f 



