eigenmann: the cheirodontin^. 65 



C. stenodon are also quite distinct from the rest of the species. This is the only 

 genus of Characins reaching the Pacific slope of Chili, where at Puerto Montt it 

 also attains the southernmost latitude recorded for the Characins. 



Key to the Species of Cheirodon. 

 a. A naked area about the entire distal margin of the tliird suborbital, very wide beliind it; elongate, depth 3 or 

 more in the length; mouth moderate; teeth broad-tipped with narrow bases; anal short, 12-15, the 

 tip of the first developed ray extending beyond the tip of the last; caudal peduncle slender, about 

 twice as long as deep. (Not examined in C. Tpisciculus.) 



b. Maxillary with two teeth ■ [M. pisciculus Girard. 



66. Maxillary with one tooth 35. annae McAtee. 



aa. Second suborbital in contact with the preopercle at least below; anal emarginate 17-27. 



c. Mouth minute or moderate; teeth broad-tipped. 



d. Fifteen to twenty interhaemals,'''^ extending from near base of last anal ray to caudal, with broad, 

 wing-hke lateral processes in the male; a naked area along the entire posterior edge of the 

 tliird suborbital. 

 e. Three, more rarely two, maxillary teeth; maxillary very little more than half the length of 

 the eye, its margin straight; premaxiUary with five teeth; A. 18-19; eighteen to twenty- 

 three interhsemals from near base or beliind tip of last anal to caudal; base of anal equals 



length of caudal peduncle; largest about 25 mm 36. insignis Steindachner. 



ee. Two maxillary teeth; maxillary about half the length of the eye, its margin but little curved; 

 premaxiUary with four teeth; A. 19-24; fifteen to twenty interhsemals, extending from near 

 base of last anal ray to caudal ; base of anal much longer than caudal peduncle. Length of 



largest recorded specimen 39 mm 37. parahybae Eigenmann. 



eee. One maxillary tooth; maxillary about half the length of the eye, its margin strongly convex; 

 premaxillary with four or five teeth; A.17-24; twenty or more interhaemals; extending from 

 near base of last anal ray to caudal. Largest recorded specimen, 60 mm. 



38. interruptus Jenyns. 



39. monodon Cope. 



40. ibicuhiensis Eigenmann. 

 dd. Eight to thirteen interhtemals extending from near tip of last anal ray to caudal ; base of anal equals 



caudal peduncle and middle caudal rays; maxillary scarcely reaching eye; cheeks with a 

 naked wedge behind the second suborbital. 

 /. Dorsal with black spot along the base of the anteriorrays; A. 20-22; scales 32-34; premaxillary 



with four teeth, maxillary with two; a spot across the entire caudal peduncle. 



41. liolomelas Eigenmann. 



jf. Dorsal without a distinct black spot. 



g. No caudal spot or other definite markings; premaxillary with five teeth; maxillary with 



two; about nine weak interhaemals. A. 23; scales 36 42. madeirae Eigenmann. 



gg. A large conspicuous caudal spot sometimes continued to the end of the middle rays. 

 h. Anal plain; scales 31-36; premaxillary with four or five teeth, maxillary usually with 

 two; nine to thirteen interhaemals, occupying half the distance between the anal 



and caudal; A. 19-27 43. piaba Liitken. 



cc. Mouth moderate; teeth in premaxillary narrow, five to nine in number; maxillary teeth two-tliirds to 

 '' See also insignis, in which there may be only eight. 



