264 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



origin of ventrals ; maxillary toothless, 

 extending somewhat beyond front 

 margin of orbit; head 35-3.5; depth 

 2J-2J; A. 38-41. Very greatly 

 compressed. 



16. cancanus (Steindachner). 

 qq. Humeral spot circular or vertically elongate. 



II. Depth 2-2.2 ; scales 8 or 9-36 

 to 40-8 or 9 ; a humeral and 

 a caudal spot ; maxillary 

 with one tooth ; head 3.66 ; 

 depth 2-2.2; A. 38-39; 

 dorsal and ventral outlines 

 equally curved. 



17. atratocnsis (Eigenmann). 

 uu. Body more elongate, humeral 



spot very conspicuous. 

 Anal rays 38-41. A silvery 

 lateral band, a humeral spot. 

 Dorsal a little behind the ori- 

 gin of the ventrals ; the an- 

 terior anal rays elongate. 

 Maxillary extending to near 

 the anterior margin of the 

 eye. Depth 2.4-2.8 ; head 

 3.5; scales 8-37 to 40 -10. 

 18. stilbe (Cope). 

 pp. Dorsal with a broad, oblique, dark band across the 

 middle, or plain. Scales 8-39-7 ; maxillary extends 

 a little beyond the origin of the eye ; D. 1 1 ; A. 3 1 ; 

 depth 2f ; head 3|. 19. bartlettii (Giinther). 



aa. Anal rays 26-29, rarely 31. 



V. A series of seven deep brown longitudinal bands. Maxillary extending little, if any, 

 beyond anterior margin of eye, with one tooth. Head 3.5 ; depth a little more than 2 in 

 the length. A. 27; scales 5-31-4. (See also under ^?>«a«//«/;«.) 



20. steindacliHcri (Eigenmann). 

 vv. A single lateral band or none. 



w. Caudal without vertical band. 

 X. Scales 28-35. 



y. A caudal spot. 



s. Shoulder spot horizontally oval, well defined. 



A. Scales in 18 or 19 rows; A. 28-32.1 13. abramis, which see. 



AA. Scales in 11-16 rows. 14. bimaculatiis, which see. 



AAA. Scales 7-34-6. Lateral band black. Scales in 14 rows. 



Dorsal fin behind the base of the ventrals. Maxillary with 



