Fish-fauna of the Bio de la Plata. 13 



the head one fourth ; interorbital space convex, its width 

 being more than the diameter of the eye, which is one fourth 

 of the length of the head. The maxillary extends to, or very 

 little beyond, the front margin of the eye. Origin of the 

 dorsal fin above the root of the ventral. Caudal fin not scaly. 

 There are eight series of scales between the lateral line and 

 the ventral fin. Silvery, sometimes with a dark spot above 

 the commencement of the lateral line ; a black caudal spot is 

 generally absent. 



Several specimens, measuring from 3 to 5^ inches, were 

 collected in the Rio de Cordova by E. Fielding, Esq. 



47. Brycon orthotamia, Gthr. (an =B. Lunclii, Ltk. ?). 



48. Chalcinus paranensis, sp. n. 



D. 11. A. 30. V. 7. L. lat. 33. L. transv. 6/3|. 



The height of the body is contained twice and two thirds in 

 the total length (without caudal), the length of the head four 

 times. Operculum twice as high as long, reaching nearly to 

 the vertical from the axil of the pectoral. The scales above 

 the lateral line and in the thoracic region are larger than the 

 others. The distance of the origin of the dorsal fin from the 

 root of the caudal is two thirds of its distance from the extre- 

 mity of the snout. Pectoral one third longer than the head. 

 Silvery ; the outer parts of the fins blackish ; the middle 

 caudal rays black. 



One specimen, 5 inches long, from the Parana. 



49. Anacyrtus argenteits, Tal. 



50. Anacyrtus humeralis, Val. 



51. Salminus maxillosus, C. & V. 

 Attaining to a length of 4 feet. 



52. Xiphorhamphus Jenynsii, Gthr. 



Specimens of this species were probably confounded by 

 Valenciennes with X. hepsetus. 



53. Serrasalmo marginatus, Val. 



54. Serrasalmo spilopleura, Kner. 



55. Myletes brachypoma, Cuv. 



56. Engraulis olidus, Gthr. S 



57. Pellona jlavipinnis, Val. 



58. Sternopygiis virescens, Val. 



59. Conger conger, L. (an = C. Orliqnyanus, 



Val.?). 



