26o PATAGONIAN EXPEDITIONS: ZOOLOGY. 



fff. Anal 19; humeral spot when present not conspicuous; caudal spot not 

 continued to the tips of the middle rays ; in some specimens the lower acces- 

 sory rays of the caudal spine-like; D. 1 1 ; lat. line 30—31 ; head 3|-3j ; 

 depth 2|-3 ; eye little more than 2 in the head. insignis Steindachner. 



ee. No black caudal spot; scales about 35 in a longitudinal series, 9-10 in the lateral 

 line ; intermaxillary teeth 5, mandibular 7, maxillary 2-3 ; depth 3 in the length ; 

 D. 1 1 ; A. (2-20) 23 ; eye 3 in the head. piaba Lutken. 



14. Cheirodon pisciculus Girard. 



Clieirodon pisciculits QxxdiX^, Proc. Acad. Nat. Sci. Phila. VII, 1854, 199; 



Girard, U. S. Naval and Astronomical Expedition, 249, pi. xxxiv, figs. 



4-7, 1855 (Lagoons near Santiago, Chili ) ; Eigenmann & Eigen- 



mann, Proc. U. S. Nat. Mus., 1891. 

 Chirodon pisciculus Giinther, Cat. Fish. Brit. Mus. V, 332, 1864 (copied) ; 



Steindachner, Zool. Jahrb. Suppl. IV, 328, 1898 (source of Rio 



Maulin, Lake Llanguihue at Puerto Montt). 

 This species is known only from the types and from a specimen from 

 Puerto Montt. 



8. ASTYANAX Baird & Girard. 



Astyanax Baird & Girard, Proc. Phila. Acad. Sci. VII, 1854 ; Girard, U. 



S. Mex. Bound. Survey, 74, 1859 [aygentatus). 

 Poecihmchthys Gill, Ann. N. Y. Lye. Nat. Hist., 54, 1858 [brevoortit). 



Type : Astyanax argentatus Baird & Girard. 



Premaxillaries with two series of teeth, the first series with several teeth 

 on each side ; mandible with strong teeth in front and very small ones on 

 the sides, without conical teeth in front ; teeth of premaxillary equal or 

 graduated, their crowns ridged and denticulate. Gill-rakers setiform. 

 No predorsal spine. Maxillary with o-io teeth. Lateral line complete. 

 Form slender ; depth mostly more than 2 in the length. 



This is one of the largest genera of Characins. Its representatives are 

 found from the borders of the L^nited States to the Rio Negro on the 

 east and Peru on the west, and from Para to the Cordilleras. Some of 

 its species have a restricted range, while others [A. rutilus) have a range 

 nearly coextensive with that of the genus. Astyanax (forms like rutilus, 

 adraniis and bimaculatus) is probably one of the oldest inhabitants of 

 South America. Its allomorphism and wide distribution would indicate its 

 long establishment. Very near relatives of this genus are found in Africa. 

 The only species known to enter the Patagonian region is Astyanax 

 rutilus (Jenyns). 



