PARENTAL CARE AMONG FKESH-WATER FISHES. 



■185 



THE ARAPAI3IA. 



The most gigantic fresh-water fish — of America, at hnist— is that 

 l)est known as the pirarucu and arapaima. Scientifically it has been 

 most aptly named Ar<tpaiin<( giga.^, and it is the only species of its 

 genus, as well as family. In addition to the characters alread}^ 

 noted, which it shares with other Osteoglossoideans, it has the belly 

 rounded and not keeled, the dorsal lonirer than the anal, the ventrals 



Fiu. &J. — The I'irarucu or Arapaimu (Arapaima gicjan]. 



far behind, postorbitals excessively ditferentiated and extremely 

 jong, and numerous (about sixteen) l)ranchiostegal rays. These 

 characters, of inconsiderable importance V)y themselves, are the super- 

 ficial concomitants of important osteological jjeculiarities which 

 would necessitate too much technical detail for the present article. 

 Those who would seek further information are referred to an article 

 on the '' Cranial osteology of the families OsteogJo!<sida\ Panto- 



Fni. 70. — The rirarucu { Araijuiiiia i/iiju.s). Head uular.i4od. Al'iei' ValeiKiouncs. 



(/onti(he, and Phrdctolamkla'^^'' by W. G. Ridewood, in the Journal 

 of the Linnean Society for 1895 (vol. 29, pp. 252-282, pi. 30-32). 



The i^irarucu is knowit by this name, according to Castelnau, 

 among all the tribes Avhich live along the Amazon. The name is said 

 to be a Guarani word meaning red fish. Arapaima is also a native 

 name. 



The pirarucu is unquestionably the largest fresh-water fish of 

 America, if not of the world, as has been claimed. It has, according 



