342 Mr. C. T. Regan on the FisJies of the 



the lateral line ; a dark band from eye to lateral blotch ; a 

 dark bar or spot below tlie eye ; a white line from eye to 

 nostril and beyond ; often a large dark oeellus on the upper 

 part of base of caudal, this varying considerably and some- 

 times completely wanting ; posterior part of soft dorsal and 

 anal with oblique dark stripes ; dark stripes on the caudal 

 more or less oblique if an ocellus be present, vertical if it be 

 absent. 



Rio Paraguay; Rio Grande do Sul. 



1. (76 ram.) Descalvados, Matto Grosso. Dr. Ternetz. 



2. (119 mm.) Parafruavan Cliaco. Dr. Ternetz. 



3. (120 mm.) Luqui, rarapuay. Dr. A. Borelli. 



4. (95 mm.) Paraguavau Cliaco. Graham Kerr, Esq. 

 5-6. (88and96mm.) Babia >»''ep:ra, N. Chaco. G. Boggiani. 



7-9. (38-82 mm.) Carandasinhn, Matto Grosso. Dr. A. Borelli. 

 10. (04 mm.) Rio Grande do Sul. Dr. H. voa Ihering. 



14. Acara dursigera. 



Acara dorsigera, Heck. Ann. Mas. Wien, ii. 1840, p. 348 ; Giinth. Cat. 

 Fish. iv. p. 280 (1802); Steind. Sitzb. Ak. Wien, Ixxi. 1875, p. 76; 

 Pellegr. M6m. Soc. Zool. France, xvi. 1903, p. 174 (1904). 



Depth of body 2i in the length, length of head 2^-2i. 

 Head very similar to that of A. tetramerus, but with 2 series 

 of scales on the cheek and 1 series on the prseoperculum ; 

 6 gill-rakers on the lower part of anterior arch. Scales 

 23-.24 % Dorsal XIII-XIV 7-10. Anal III 8. Dorsal 

 and anal fins scaleless. Pectoral as long as the head. 

 Caudal rounded. Caudal peduncle ^ as long as deep. 

 Olivaceous, with 7 or 8 more or less distinct darker cross- 

 bars ; a dark blotch below the ninth to eleventh scales of 

 the lateral line; a dark longitudinal band from eye to lateral 

 blotch ; a dark spot on the spinous dorsal between the eighth 

 and tenth spines ; soft dorsal, anal, and caudal with series of 

 alternate light and dark spots. 



R. Amazon ; R. Paraguay. 



The examples described by Heckel and Steindachner 

 measure up to 53 mm. in total length. 



15. Acara Thayeri. 



Acara Thayeri, Steind. Sitzb. Ak. Wien, Ixxi. 1875, p. 68, pi. i. fig. 2 ; 

 Pellegr. M6m. Soc. ZuoX. France, xvi. 1903, p. 175 (1904). 



Depth of body 2 in the length, length of head 3. Snout 

 shorter than postorbital part of head. Diameter of eye 3 in 

 the length of head, interorbital w^idth 2§-2|. IVlaxillary not 

 extending to below the eye ; jaws equal anteriorly ; cheek 



