258 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



lih. Mandible with a pair of conical teeth behind the middle of the front series. 



q. Both series of teeth of upper jaw simply compressed ; dorsal beginning above 

 or behind ventrals. 

 r. Lateral line complete. Micralestes Boulenger (African). 



;';•. Lateral line incomplete. Phenacogrammiis Eigenmann (African). 



qq. Inner series of teeth of the upper jaw tuberculate ; no maxillary teeth ; a series 

 of large, compressed multicuspid teeth in the lower jaw, similar to those in 

 Astyanax. 

 s. A parietal, no frontal fontanel. Brycinns Cuv. & Val. (African). 



ss. A parietal and a frontal fontanel. 



t. Origin of dorsal over or behind ventrals. Myletes Cuvier (African). 

 //. Origin of dorsal in front of ventrals ; premaxillary teeth imperfectly 

 in three series. Bryconisthiops Giinther (African). 



gg. Premaxillary teeth in three or more series. 



Ji. Lower lip very broad, pendant. Othonophancs Eigenmann. 



itu. Lower lip normal. 



V. Mandible frequently with a pair of conical teeth behind the middle of the front 

 series except sometimes in Mcgalobrycon. 

 w. Scales moderate, 35 in the lateral line; anal with 20-23 rays. 



BryconcEtliiops Giinther (African). 

 ivw. Scales moderate or small, more than 45 in the lateral line ; anal rays 

 more than 20. 

 X. Lower jaw with a second series of teeth, at least on the sides. 



Brycon Miiller & Troschel. 

 y. Anal rays more than 30. [Chalcinopsis Kner). 



yy. Anal rays fewer than 30 ; belly not keeled. 



z. Lower jaw sometimes without conical teeth 



(^Mcgalobrycon Giinther.) 



S3. Lower jaw with a pair of conical teeth. {Brycon.) 



vv. Lower jaw without a pair of conical teeth in front, and without an inner .series 



of conical teeth on the sides. 



A. Ventrals below anterior dorsal rays; anal with 32-38 rays; maxillary 



without teeth ; premaxillary with two or three, mandible with a single 



series of teeth. Bryconops Kner. 



A A. Ventrals in front of dorsal or just under anterior rays. Anal short, of 



12-22 rays; maxillary with a few blunt teeth; three series of notched 



teeth in the premaxillary, a single series in the lower jaw. 



Creagrutus Giinther. 



7. CHEIRODON Girard. 



Ckeirodon G'waxd, Proc. Acad. Nat. Sci. Phila., VII, 1854, 199 [pisciculus). 



Type: Cheirodou pisciculus Girard. 



Premaxillary, mandible and sometimes the anterior part of "the maxillary 

 each with a single series of multicuspid incisors ; dorsal short ; opercle 



