388 Mr. C. T. R",oan— yi Revision of 



and showing further agreement in their oblong or elongate 

 form, rounded abdomen, flattish upper surface of tiie head, 

 large scales, short dorsal and anal fins, &c. 



I give a list of the specimens in the British Museum 

 collection, considerably augmented in the last few years by 

 gifts of examples from tiie Amazon (Herr J. Paul Arnold), 

 Obidos (Herr A. Rachovv), Manaos (E. Stanley Sutton, Esq.), 

 and Colombia (Sir Bryan Leighton), and by the acquisition 

 of a set from Professor Eigenmann's collection made in 

 British Guiana. 



1. Chalceus. 



Chalceus, Cuv. Mem. Mus. Paris, iv. 1818, p. 454 ; Giinth. Cat. Fish, v, 



p. 333 (1864). 

 Plethodectes, Cope, Proc. Amer. Phil. Soc. xi. 1871, p. 563. 

 Pellegrinina, Fowler, Proc. Acad. Philad. 1906, p. 442. 



Body oblong, compressed. Scales large, unequal ; lateral 

 line present, running low. Mouth moderate, terminal ; 

 prseraaxillary teeth triserial, the outer tricuspid, the inner 

 pentacuspid ; maxillary toothed; mandibulary teet'i biserial, 

 the outer tri- or pentacuspid, the inner series conical, small, 

 except for an enlarged median pair ; ])alate toothless. Nos- 

 trils close together. Gill-membranes free. Dorsal and anal 

 fins short ; adipose fin present. 



1. Chalceus macrolepidotus. 



Chalceus macrolepidotus, Cuv. M^m. Mus. Paris, iv. 1818, p. 454, 



pi. xxi. fig. 1 ; Gunth. Cat. Fish. v. p. 333 (1864). 

 Pellegrinina heterolepis, Fowler, Proc. Acad. Philad. 1906, p. 442, fig. 



Depth of body 3| to 4 in the length , length of head 3^ to 

 3|. Diameter of eye 3 to 4 in length of head, interorbital 

 width 2 to 2^. 20 or 21 scales in a longitudinal series from 

 upper angle of gill-cleft to base of caudal, 37 in the lateral 

 line. Dorsal 12; origin behind base of pelvics, equidistant 

 from tip of snout and end of middle caudal rays. Anal 12. 



Guiana. 



1. 150 mm. Essequibo. Ehrhardt. 



2-3. 110 mm. Brit. Guiana. Schomburgk. 



4. 65 mm. Surinam. Kappler. 



2. Chalceus ery thrums. 

 Plethodectes erythrurus, Cope, Proc. Amer. Phil. Soc. xi. 1871, p. 563, 



fig. 

 Depth of body 3§ in the length, length of head 3|. 



