3. IIETEROTIS, 379 



2. ARAPAIMA*. 



Sudis, sp., Cuv. lik/ne Aiiint. (not liajin.). 



Arapaiuia, Midler,' Ahhumll. Ak. Wiss. Berl. 1846, p. 191, 



Vastves, Vuv. <^- Vnl. xix. p. 4;J3. 



Eody ratlicr elongate, compressed ; head dejiressed ; abdomen 

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

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

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

 sphenoid, os linguale, and hyoideuHl. Pectoral tins of moderate 

 length ; vertical fins scaly. (Jill-membranes separate ; branchio- 

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

 chial organ. 



Brazils and Guyanas. 



1. Arapaima gigas. 



Sudis gigas, Cuv. lik/iie Anini. ; Ayass. in Spix, Pise. Bras. p. 31, 

 (anat.) tab. B (skeleton j Scliomburyk, Fish. Gtiian.-p. 198, tab. 11) 

 (not good). 



pirarucu, Spir, I. c. pi. IG (bad). 



Vastres cuviori, Cuv. i>f Val. xix. p. 441, pis. 579 & 580 (head). 



mapai, Cur. i^- Val. xix. p. 449, pis. 680 & 581 (head). 



agassizii, Cuv. ^- Val. xix. p. 450. 



avapainia, Cuv. <i)- ?'«/. xix. p. 401. 



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. 



a. Eight feet long ; stuffed. British Guyana. Presented Dy iSir R. 



Schomburgk. 



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



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



Schomburgk. 



d. Parts of the skeleton of a young example. 



e. Hyoi^ bone of a large example. 



3. HBTEROTIS. 



Sudis, sp., Ctiv. Itegnc Anim. 

 lleterotis, Ehrenherg. 



Body rather elongate, compressed ; head compressed ; abdomen 

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

 barbels none. A single series of small 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 Vasfres jussiei and Vasfrcs condaminei have been given by 

 Valenciennes to liyoid bones of Arapaima or Ostcuglossitm, Cuv. & Val. xix. 

 p. 462 



