ARAPAIMAS. 



477 



pterotic bone devoid of a cavity in its interior. Externally these fishes may be 

 recognised by the naked body and the absence of barbels ; the fatty fin being 

 absent, and the medium-sized dorsal opposite the anal. Internally the air-bladder 

 is large and simple ; and the eggs, as in the last family, fall into the abdominal 

 cavity. Represented by rather more than a dozen species, the largest of which 

 seldom exceeds 8 inches in length, these fish are of especial interest from a 

 distributional point of view, since they occur in such isolated areas as New 

 Zealand, New South Wales, Tasmania, and the southern extremity of South 

 America. From their spotted bodies, the New Zealand representatives of the genus 

 were formerly known as trout by the colonists. An allied New Zealand genus 

 (Neochanna), represented by a single species, differs in the absence of pelvic fins ; 

 all the known specimens of this singular form having been found buried in burrows 

 of clay or hard mud at a considerable distance from the water. 



BRAZILIAN ARAPAIMA (^ liat. size). 



The Arapaimas, — Family Osteoglossid^e. 



Agreeing with the last family in the conformation of the base of the skull, 

 the large tropical fresh- water fishes, which may be collectively known as arapaimas 

 (although this name properly belongs only to the Brazilian species here figured), 



