OSTEOGLOSSID FISHES. 



89 



head and gill-covers. The pelvic fins are reduced or absent. 

 The air-bladder is large and complex in structure ; it is connected 

 with the ear by forwardly directed processes which enlarge at 

 their ends into air-vesicles embedded in the side of the hinder 

 part of the cranium, and it sends also a pair of processes back 

 into the tail region. 



The Osteoglossida? are a sharply delimited family distinguished 

 by the sculpturing of the superficial bones of the skull, the robust 

 character of the cheek-plates, the meeting of the parietal bones, 

 the sutural union of the nasal bones with one another and with 

 the anterior ends of the frontal bones, and the presence of 

 a stout, peg-like process of the parasphenoid for articulation 

 with the entopterygoid. The scales are large and thick, and with 

 a mosaic-like structure. The dorsal and anal fins are set back, 

 and their bases are more or less extended. The trunk vertebrae 

 have stout transverse processes for the attachment of the ribs (see 



x 4g? 



Fig. 50. — Arapaima gigas. 

 (From Boulenger, Camb. Nat. Hist., vii, 1904.) 



skeleton of Arapaima, 1035, Table-case 50). The Osteoglossidse 

 are fresh-water fishes of the tropics. The Arapaima {Arapaima 

 gigas, fig. 50, 1033 and 1031, Table-case 51, and skeleton, 1035, 

 Table-case 50), locally known as the "Pirarucu,"" is a great fish 

 of the rivers of Brazil and the Guianas, attaining a length of 

 15 feet and a weight of 400 lbs. or more. The larger specimen 

 in Table-case 51 is a little under 8 feet in length. The scales 

 are large (250, Wall-case 7), and in the living fish are greenish- 

 brown, with a reddish hind border. The Arapaima is highly 

 esteemed as an article of food ; the flesh is cured and salted in 

 a manner similar to that of Cod-fish, and is an important article 

 of local commerce. In the floor of the mouth of the fish is a 

 bone covered with small teeth of uniform size (249) which the 

 natives use as a rasp for scraping into a pulp the flesh of gourds 

 and similar vegetables. 



Osteo- 

 fflossidse. 



