was wrong, as the labyrinth c-(»nt;iins air iu 

 its canals and spirals. 



Labyrinth breathing is done in this wise: 

 The fish rises to the surface of the water 

 and takes in a fresh air supj^ly through the 

 mouth, the caudal and abdominal muscles 

 exert jiressure upon the swimming bladder 

 whereby air is forced through the inner 

 opening into the labyrinth. 



All labyx'inth fishes are so much liound 

 to direct air breathing that they Avill die 

 even in richly oxygenated water if denied 

 access to the surface — for instance, by 

 means of a submerged net. 



Many of these fishes, therefore, are in- 

 habitants of mud- 

 dy or foul pools. 

 Many can survive 

 temporary drying 

 up of their home 

 waters either by 

 burrowing or 

 l>urying them- 

 selves in the mud, 

 or, as in the case 

 of the climbing 

 perch (anaba.s), 

 by migrating in 

 search of a new 

 home. 



Others live only 

 in permanent 

 bodies of water. 

 They are all car- 

 nivorous, feeding 



POLYCANTHUS SPECIES— Male and Female 



One of the labyrinth fishes. Owing to the labyrinth formation 

 and <-onseciuent surface breathing, a large number of these fish 

 can be kept in a small aquarium, without plants if necessary 



upon all living animal 

 substances obtainable by them. 



They are all trojncal fishes of the Old 

 World. . The labyrinth fishes were for- 

 merly all put into one family, but they ate 

 now separated into three — two in the sulv 

 order of Persedoces and one into the order 

 of Perciform Spiny-rayed fishes. 



In the first order come the families of 

 climbing ])erches {Anahantida') and Snake- 

 head fishes {Ophiocephalichv) . It is these 

 two families we will speak of in this article. 



The climbing perches have an elongate, 

 perchlike body, slightly compressed. The 



gill covers are toothed at the edges. The 

 dorsal is longer than the anal, the ventrals 

 have one spine. The mouth is wide, reach- 

 ing back to beneath the middle of the eye. 

 These fishes live in the fresh water and 

 river mouths of Asia (four species) and 

 Africa (five species). The typical si)ecies 

 has been the subject of many widely and 

 varying fables. 



Daldorf, the first describer, said he had 

 seen the fish climbing tij) the furrows in a 

 palm near a pond, the fish bracing itself 

 against the furrow with the spines of its 

 spread gill covers, the tail moving to and 

 fro, the spines of the anal fins braced against 

 the tree, beating 

 the gill covers al- 

 ternately and so 

 progressing step 

 liy step. Later 

 travelers tell of 

 no such aerial ex- 

 cursions, so that 

 today tree climb- 

 ing is considered 

 to be simply an 

 idle fancy. The 

 Indian names of 

 the first, L ndis- 

 colli, Paumi-eri, 

 N o z a g n i , etc . , 

 meaning "tree- 

 climbers," not- 

 withstanding. 

 The truth is the climbing jjerch can live 

 for a long time without water and can move 

 about on the ground. As the summer sun 

 licks \x\) more and more the home waters of 

 the fish, the latter collect in the water- 

 holding pools or in the damp mud. Finallj" 

 as these, too, dry out, they start to seek 

 other ponds. Hundreds of them leave the 

 spot in difi^"erent directions, overcoming all 

 obstacles. The gill covers are wide open 

 on these migrations and the pectoaal fins 

 spread out. The former are bent back as 

 if hinged, the sharp gill cover sjnnes seek- 

 ing a hold on the ground; then the body 



.50 



