68 TELEOSTEI. PIIYSOSTOMI. 





the seas than in the fresh waters. Among the Apodes the spined 

 freshwater eels (RhynchoMellidce) and the NotacantJtidee, Giiuther, 

 have been placed. 



Geographical Distribution. Fresh and brackish waters of tropical 

 Asia and America; also Western Australia and Van Diemen's 

 land. 



Synopsis of Indian Genera. 



First group. AMPHIPNINA. 



Humeral arch not attached to the skull ; an accessory breathing- 

 apparatus. Scales present. 



Palatine teeth in a single row 1. AMPHIPNOUS. 



Second group. SYMBRANCHINA. 



Humeral arch attached to the skull. No accessory breathing- 

 apparatus. Scales absent. 



Gills rudimentary 2. MONOPTEBUS. 



Gills well developed 



First group. AMPHIPNINA. 



1. Genus AMPHIPNOUS, Miiller. 

 Syn. Pneumabranchus, McClelland. 



Branchiostegals six. Gill-membranes almost entirely grown to 

 the isthmus, and having a single transverse opening. Three bran- 

 chial arches with the laminae rudimentary, divided by. narrow slits. 

 A respiratory air-sac exists on the neck behind the head and com- 

 municates with the gill-cavity. Palatine teeth in a single, well- 

 developed row. Scales present and arranged in longitudinal rows. 



This amphibious fish, when kept in an aquarium, may be observed 

 constantly rising to the surface for the purpose of respiring atmo- 

 spheric air direct. It usually remains with its snout close to the 

 surface, and in like manner lies in the grassy sides of ponds and 

 stagnant pieces of water, so that without trouble it may obtain 

 access to air. 



In Amphipnous cuchia we find that " of all the arches, the second 

 alone possesses laminae for the purposes of breathing ; and these 

 consist merely of a few long fibrils attached to the middle of the 

 arch, and occupying but a very small extent of its surface ; the 

 third supports, in the place of laminae, a thick and semi-transparent 

 tissue, which in large individuals of the species possesses a fringed 

 or denticulated appearance at its edge ; whilst the first and fourth 

 are bare, having only the membrane that fills up the space between 



