216 MEMOIRS OF THE CARNEGIE MUSEUM 



Callichthys lecviceps Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 

 309 (= male). 



Callichthys loricatus Gronow, Cat. Fish., ed. Gray, 1854, 157. 



Callichthys hemiphractus Hensel, Archiv fur Naturg., I, 1868, 374 (Costa da Serra; 

 = the young). 

 Ten specimens, 69-142 mm. Small Creek at Holmia. (C. M. Cat. No. 1570 



a-c; I. U. Cat. No. 11985.) 



One specimen, 129 mm. Chipoo Creek. (C. M. Cat. No. 1571.) 



One specimen, 106 mm. Nickaparoo Creek. (C. M. Cat. No. 1572.) 



Seven specimens, 117-149 mm. Upper Essequibo. (C. M. Cat. No. 1573 



a-b; I. U. Cat. No. 11986.) 



Fifteen specimens, 60-129 mm. Kumaka. (C. M. Cat. No. 1574a-c; I. U. 



Cat. No. 11987.) 



One specimen, 125 mm. Pacopoo Pass. (C. M. Cat. No. 2208.) 



I have also examined the specimens recorded by Bleeker, and now in the 



Leiden Museum, and those in Amsterdam. 



28—29 

 Head 4; depth 4.66-5, equal to its width; D. 1,6; A. 5.5; plates .„ „,. . 



Head depressed, tail compressed; eye 6.5-8 in interorbital ; inner rictal barbel 

 reaching to near or beyond the tip of the humeral process; nuchal plates about 

 twice as wide as the plates immediately behind them; snout broad, rounded; no 

 teeth in the upper jaw, those in the lower jaw interrupted in the middle, confined 

 to the side of the jaw. About fourteen small azygous plates in front of the adipose; 

 fins all rounded. Uniform ashy or slaty, or more or less mottled or spotted; no 

 definite markings. 



HOPLOSTERNUM Gill. 



Callichthys Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 294 (sp.). 

 Hoplostermim Gill, Ann. Lye. Nat. Hist. N. Y., VI, 1858, 395 (Icevigatum = 



littorale) . 



Type, Callichthys Icevigatus Valenciennes. 



Characters given in the key. 



Key to the Guiana Species of Hoplosternum. 

 o. Caudal deeply emarginate; eight or nine azygous plates in front of the adipose, usually one between 

 each pair of plates; one, rarely two, pairs of plates behind the dorsal without the azygous plates; 

 three pairs of plates between occipital and dorsal. Uniform dark brown or black., littorale. 

 aa. Caudal rounded or but slightly emarginate; the azygous plates usually more numerous than the 

 pairs of plates they separate; several pairs of plates meeting behind the dorsal; two pairs of 

 plates between occipital and dorsal, the second pair notched to receive the dorsal fulcrum. 

 Sides spotted or mottled thoracatum. 



