3. UETEROTIS. 379 



2. ARAPAIMA*. 



Sudis, sp., Cuv. Hegne Anim. (not Rajin.). 



Arapaiuia, Miiller, Ahhundl. Ak. Wiss. lierl. 1846, p. 191. 



Vastres, Cuv. &;■ Val. xix. p. 483. 



Body rather elongate, compressed ; head depressed ; abdomen 

 rounded. Cleft of the mouth wide, with the lower jaw prominent; 

 barbels none. Jaws with an outer series of conical small teeth ; 

 broad bands of rasp-like teeth on the vomer, palatines, pterygoids, 

 sphenoid, os linguale, and hyoideuni. Pectoral lins of moderate 

 length ; vertical fins scaly. Gill-membranes separate ; branchio- 

 stegals rather numerous. Air-bladder — (?). No accessory bran- 

 chial organ. 



Erazils and Guyanas. 



1. Arapaima gigas. 



Sudis gigas, Citv. Rk/ne Anim. ; Agass. in Spi.v, Pise. Bras. p. 31, 

 (anat.) tab. B (skeleton; Schomhuryk, Fish. Guian. p. 198, tab. 11) 

 (not good). 



pirarucu, Sjnx, I. c. pi. 10 (bad). 



Vastres cuvieri, Cin: ^- Val. xix. p. 441, pis. 579 & 580 (head). 



mapae, Cuv. ^ Val. xix. p. 449, pis. 580 & 581 (head). 



agassizii, Cuv. ^- Val. xix. p. 456. 



arapaima, Cuv. ^- Val. xix. p. 461. 



B. 16. D. 34-37. A. 30-32. V. 6. L. lat. 56. L. transv. 6^/6 

 (between dorsal and anal). Vert. 38/41. 



Maxillary reaching to below the orbit. The length of the head 

 is rather less than one-fourth of the total (without caudal). 



Brazils and Guyanas. 



fl. Eight feet long; stuffed. British Guyana, Presented by Sir E. 

 !Schombuj-gk. 



b. Seven feet long : stuffed. Bahia. Purchased of Mr. Stevens. 



c. Skeleton, six feet long. British Guyana. Presented by Sir E. 



Schomburgk. 

 (L Parts of the skeleton of a young example. 

 e. Hyoid bone of a large example. 



3. HETEROTIS. 



Sudis, sp., Cnv. JRegne Anim. 

 Heterotis, Ehrenhery. 



Body rather elongate, compressed ; head compressed ; abdomen 

 rounded. Cleft of the mouth rather small, with the jaws subcqual ; 

 barbels none. A single series of smaU teeth in the jaws ; ptery- 

 goids and hyoid with a patch of small conical teeth ; none on the 

 vomer or palatine bones. Gill-membranes separate, with eight 

 branchiostegals ; the fourth branchial arch with a spiral accessory 



* The names of Vastres jussiei and Vastres condaminei have been given by 

 Valenciennes to hjoid bones of Araipaima or Osteoylossum, Cuv. & Val. sis. 

 p. 402. 



