212 MR. C. TATE REGAN ON THE 
11. Puecostomus corpovs#. (Plate IX. fig. 3.) 
Plecostomus cordove Giinth. Ann. Mag. Nat. Hist. (5) vi. 1880, p. 11. 
Depth of body nearly 8 times in the total length, length of head 32 times. Depth 
of head 24 times in its length, breadth of head 1) times, length of snout 1 times, 
diameter of eye 10 times, interorbital width 3 times. Length of mandibular ramus 
14 times in the interorbital width. Snout broad, rounded; supraorbital edges 
slightly raised; supraoccipital with low median ridge; temporal plates carinate. 
Scutes spinulose, those of the upper series and the anterior of the second series 
carinate, 30 in a longitudinal series, 10 between dorsal and adipose fin, 17 between 
anal and caudal. Supraoccipital bordered posteriorly by a median scute and by one 
on each side. Lower surface of head and abdomen almost completely covered with 
small granular scales. D.I 7, the first ray nearly as long as the head, the last half 
as long; length of base of dorsal less than its distance from the adipose fin. A.I 4. 
Pectoral spine extending to base of ventral. Caudal emarginate, the inner rays equal 
to 3 the length of the outer, which are as long as the head. Caudal peduncle 
41 times as long as deep. Head and body with dark spots, fins with irregular dark 
cross-bars. 
Total length 22) mm. 
One specimen: Cordova, Argentine Republic. 
12. PLecostoMuS BORELLII. (Plate IX. fig. 2.) 
Plecostomus borellii Bouleng. Boll. Mus. Torino, xii. 1897, no. 279, p. 2. 
od 
Depth of body nearly 7 times in the total length, length of head 53 times. Depth 
of head 1% times in its length, breadth of heal once, length of snout 1? times, 
diameter of eye 74 times, interorbital width 3 times. Length of mandibular ramus 
14 times in the interorbital width. Snout broad, rounded; supraorbital margins not 
raised; supraoccipital with low median ridge; temporal plates weakly carinate. 
Scutes spinulose, the anterior of the two upper series weakly carinate, 28 in a 
longitudinal series, 9 between dorsal and adipose fin, 15 between anal and candal. 
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 $ the length of head, the last 3 as long; length of base of dorsal 
a little less than its distance from the adipose fin. A. I 4. Pectoral spine not 
extending beyond base of ventral. Caudal slightly emarginate, the outer rays as long 
as the head, the inner $ as long. Caudal peduncle 3} times as long as deep. Blackish 
spots on the dorsal fin. 
Total length 180 mm, 
One specimen: Bolivia. 
