19. TETRAGONOPTERUS. 321 



/3. Tlie height of the body is less than one-half of the total length 



(without caudal). 



* The dorsal fin commences distincth- heliind the origin of the ventral. 



9. Tetragonopterus brevirostris. 



Chalceus brevirostiis, Giinth. Proc. Zool. Soc. 1859, p. 420. 

 D. 11. A. 37. L. lat. 46. L. transv. 6/7. 



The height of the body is somewhat less than one-third of the 

 total length (without caudal), the length of the head one-fourth. 

 Interorbital space rather convex, its width being equal to the dia- 

 meter of the eye, which is one-third of the length of the head, and a 

 little longer than the snout. The upper profile is scarcely concave 

 above the eye. The maxillaiy extends to below the anterior margin 

 of the orbit. The vertical from the origin of the dorsal falls behind 

 the root of the ventrals, and the last dorsal rays are vertically above 

 the anterior rays of the anal fin. The j^ectoral reaches somewhat 

 beyond the base of the ventral. Scales very thin. Bright silvery ; 

 a black band runs from the base of the caudal fin along its middle 

 rays. 



Western Andes of Ecuador. 



a-h. Types of the species, 31 lines long. From Mr. Eraser's Col- 

 lection. 



10. Tetragonopterus abramis. 

 J&iyns, Zool. Beciyle, Finh. p. 123. tab. 23. fig. 1. 

 D. 11. A. 28-31. L. lat. 43-47. L. transv. 10/8. Vert. 13/18. 



The height of the body is two-fifths of the total length (without 

 caudal), the length of the head rather less than one-foui'th. Inter- 

 orbital space very convex, its width being considerably more than 

 the diameter of the eye, which is two-sevenths of the length of the 

 head. The upper profile is a little concave above the eye. The 

 maxillary extends somewhat beyond the anterior edge of the orbit. 

 The vertical from the origin of the dorsal faUs behind the root of the 

 ventrals ; the pectoral reaches to the ventral. An indistinct blackish 

 humeral spot ; another on the root of the caudal ; both spots some- 

 times absent. 



Rio Parana ; Essequibo. 

 a-h. Adult. British Guiana. Presented by Sir R. Schomburgk. 

 c-cl. Fine specimens. Essequibo. From Mr. Ehrhardt's Collection. 

 €. Adult : skeleton. British Guiana. Presented by Sir R. Schom- 

 burgk. 



11. Tetragonopterus maculatus. 



Charax no. 54, Grcmov. Mm. Ichth. i. p. 19. tab. 1. fig, 5. 

 Albula maculata, L. Mu». Ad. Fred. p. 78. tab. 32. fig. 2. 

 Salmo bimaculatus, L. Si/st. Nat. i. p. 613 (not svn.) ; Block, taf. 382. 



tig. 2 ; £1. Schn. p. 413. 

 Tetragonopterus maculatus, Miill. ^- Trosch. Jlui: Ichth. i. p. 14. taf. 3. 



fig. 4 (teeth). 



VOL, V. V 



