452 



PARENTAL CARE AMONG FRESH-WATER FISHES. 



the best evidence as to the ovigeroiis period has been furnished by 

 the Netunia hai'hvs or commersonii^ a species very abundant in south- 

 ern Brazil, Avhere it is known as the bagre. H. von Ihering (1889) 

 tells that in the Rio Grande do Sul the spawning season is the late 

 spring and summer — that is, during November, December, and Jan- 

 nary, The eggs of this species, by the way, have been declared to be 

 the largest of any known Teleost, being about three-fourths of an 

 inch (17 or 18 millimeters) in diameter. 



But, although most of the Tachisurines are probably oral egg car- 

 riers, all are not so, one making a peculiar kind of nest and another 

 being declared to be viviparous. 



A FRESH-WATER TACHISITRINE. 



The northern Australian fish generally known as Arius australis, 

 but which some modern systematists would call Hexanematichthys 



australis^ is a nest 

 maker, but makes a 

 nest different from 

 those prepared by the 

 glanis and the Ameri- 

 can catfishes. 



The species is an in- 

 habitant of the Hunter 

 River, Richmond Riv- 

 er, and the Boyne, and 

 it was in the last that 

 Semon found it in 

 abundance and first 

 noticed its nesting hab- 

 its. By the English 

 colonists it is called 

 jewfish, and by the 

 native blacks bolla. 

 Inasmuch as jewfish is 

 better known in con- 

 nection with several 

 other fishes, bolla may 

 be a d V a n t a g e o usly 

 used. The fish has 

 the general appear- 



¥\G.^.— The hoWa. {Ilr.rancinatkhthiisaustralis). AtterGiinther. nr\na o-p flio f -i 111 i 1 i o v 



sea catfishes and slender fresh-water catfishes of America, but the 

 upper surface of the head or casque from the interorbital region 

 backward is thickly sprinkled with fine bead-like granulations. 



