eigenmann: the cheirodontin^. o 



paring this revision, I did not have access to specimens of Aphyocharax avanj 

 Fowler, Cheirodon eques Steindachner, Cheirodon agassizi Steindachner, Cheirodon 

 pulcher = nattereri Steindachner, Odontostilbe drepanon Fowler, Odontostilbe madeirce 

 Fowler, and Leptagoniates steindachneri Boulenger. 



It is quite possible that several of these are here described under other names. 

 It is possible that C. agassizi is the male of Aphyocharax pulcher, and that Odon- 

 tostilbe drepanon is Holesthes pequira. 



The Cheirodontin^. 



The subfamily Cheirodontinse (Aphyocharacinse auctorum) belongs to the large 

 family Characida;. All the species are small or even minute. The giants of the 

 subfamily are only about 90 mm. long at their best. Parqgoniates alburnus reaches 

 a length of 90 mm. The largest recorded Grundulus is 80 mm. long, the largest 

 Probolodus 81, the largest Parecbasis 80, the largest Odontostilbe microcephala 80. 

 Then follow Aphyocharax dentatus with a maximum length of 72 mm., Cheirodon 

 interruptus QO mm., Aphyocharax alburnus and pusillus 58 mm., Holesthes pequira 

 56 mm., H. heterodon 50 mm., Prionobrama paraguayensis 50 mm., and P. filigerus 

 60 mm. The rest are all under 50 mm. in length. 



Generalized type of the subfamily.— A composite of all the known species will 

 give us an idea of the ancestor of these species, assuming for the moment that they 

 had a common ancestor, which is open to some doubt. However, even if a few of 

 the genera included do not belong to this an otherwise homogeneous group, they 

 are so nearly like them that their inclusion will scarcely impair the full value of 

 the generalized type. 



The generahzed type is a fash rather under fifty millimeters, or two inches, in 

 length; compressed, oval, with symmetric dorsal and ventral outlines. Its depth 

 at the origin of the dorsal is about one-third of the length from the tip of the snout 

 to the end of the median series of scales. The head is about equal to one-fourth 

 of this length. The eye is large, about one-third as long as the head. The mouth 

 is terminal and the maxillary reaches to about the origin of the eye. The cheeks 

 and postorbital portion of the head are protected by the well-developed chain of 

 suborbital bones, of which the third is in contact with the lower hmb of the 

 preopercle, there being a naked wedge between it and the vertical hmb of the pre- 

 opercle. The teeth are in a single series, comparatively few in number, and with 

 lateral notches. They occur along the entire edge of the premaxillary, at the 

 upper angle of the maxillary, and along the front and sides of the lower jaw. The 



