FISHES OF THE FAMILY LOEICAKIID.E. 211 



anteriorly ; supraorbital edges moderately or slightly raised ; snpraoccipital with median 

 ridge ; temporal plates usually not carinate. Scutes spinulose, usually only those 

 posterior to the dorsal carinate, sometimes the anterior scutes also weakly carinate, 

 sometimes none of the scutes with distinct keels, 28-30 in a longitudinal series, 

 8-9 between dorsal and adipose fin, 14-15 between anal and caudal. Supraoccipital 

 margined posteriorly by a median scute and 1 or 2 on each side. 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 the head, the last \ as long ; length of base of dorsal 

 \\ (young) to \\ (adult) times in its distance from the adipose fin. A. I 4. Pectoral 

 spine extending to base of ventral or beyond. Caudal strongly emarginate. Caudal 

 peduncle 4-5 times as long as deep, broad and fiat below, the scutes of the fourth 

 series being strongly angulated, forming a ridge which margins the flat lower surface. 

 Dark spots on head, body, and fins, those on the dorsal usually arranged in two series 

 between each pair of rays. 



Total length 470 mm. 



Nineteen specimens (including the type of the species) : Brazil to Colombia. 



10. Plecostomus alatus. 



Hypostomus alatus Casteln. Anim. Am. Sud, p. 41, pi. xx. fig. 1 (1855). 

 Plecostomus alatus Giinth. Cat. Fish. v. p. 231 (1864) ; Liitk. Vid. Selsk. xii. 1875, p. 144. 

 Plecostomus francisci Liitk. Overs. Dan. Selsk. 1873, no. 3, p. 30; Vid. Selsk. xii. 1875, 

 p. 143. 



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

 of head If times in its length, breadth of head 1-J times, length of snout lf-lf times, 

 diameter of eye 6^ times, interorbital width 2f times. Length of mandibular ramus 

 2f times in the interorbital width. Snout broad, rounded ; supraorbital edges not 

 raised ; supraoccipital with low median ridge ; temporal plates not carinate. Scutes 

 spinulose, not carinate, 27-28 in a longitudinal series, 9 between dorsal and 

 adipose fin, 15 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. 1 7 ; the first ray as long as the 

 distance from its base to the tip of snout; length of base of dorsal equal to its 

 distance from the middle of the spine of the adipose fin. A. I 4. Pectoral spine 

 extending to anterior third of ventral. Caudal emarginate, the inner rays § the 

 length of head, the outer much produced. Caudal peduncle 3J times as long as deep. 

 Brownish, with yellow spots on head, body, and fins. 



Total length 300 mm. 



Two specimens (including the type of the species) : Araguay, San Francisco, and 

 das Velhas Rivers. 



