14. KHYTIODTJS. 305 



the root of the caudal, where it terminates in a black spot, which is 

 more distinct in young examples than in old ones. 



Brazil. 

 a-d. Fine specimens. River Capin. Purchased of Mr. Stevens. 

 e. Half-grown. River Cupai. Purchased of Mr. Stevens. 



7. Anostomus isognathus. 



Schizodon isognathus, Kner, Denkschr. Acad. Wiss. Wien, 1859, xvii. 

 p. 163. taf. 6. fig. 13. 



D. 11-12. A. 10. L. lat. 44-46. L. transv. 6 -f. 



The length of the head is a little more than one-fifth of the total 

 (without caudal) ; the lower jaw does not project beyond the upper. 

 Each jaw has the incisors crenulated, eight in number. A dark band 

 runs from the upper part of the gill-opening to the middle of the 

 fork of the caudal. (Kner.) 



Rio Cujaba. 



8. Anostomus nasutus. 



Schizodon nasutus, Kner, Denkschr. Acad. Wiss. Wien, 1859, xvii. 

 p. 164. taf. 7. fig. 14. 



D. 11-12. A. 9-10. V. 10. L. lat. 42-44. L. transv. ^f- 



The length of the head is one-fifth of the total (without caudal). 

 Snout somewhat pointed, with the upper jaw projecting beyond the 

 lower. Each jaw with eight crenulated teeth. Coloration uniform : 

 a triangular spot on the root of the caudal fin, extending over the 

 middle of its fork. (Kner.) 



Irisanga. 



14. RHYTIODUS. 



Rhytiodus, Kner, Denkschr. Acad. Wiss. Wien, 1859, xvii. p. 165. 



Dorsal fin placed before the middle of the length of the body, 

 above the ventrals ; anal short. Body oblong, covered with scales 

 of moderate or rather small size. Belly rounded. Cleft of the mouth 

 very small ; intermaxillary and mandible with a single series of 

 small compressed teeth, longitudinally keeled in front : those in the 

 upper jaw with a single point, those in the lower with two keels and 

 two points ; palate toothless. Nostrils remote from each other. 

 Gill-openings rather narrow, the gill-membrane being grown to the 

 isthmus. Eyes with a broad adipose circular membrane. 



Brazil. 



1. Rhytiodus microlepis. 



Kner, I. c. taf. 7. fig. 15. 

 B.4. D. 11-12. A. 10. V. 9-10. L. lat. 87-90. L. transv. i^ 2 - 



9-8 



The height of the body equals the length of the bead, and is con- 

 tained five times and one-third in the total (without caudal). Jaws 

 equal in length anteriorly. Coloration uniform brown. (Kner.) 



Barra do Rio Negro. 



