Labyrinthici and Holconoti 585 
the rivers of southern China and India, crossing to Formosa and 
to Africa. They are extremely tenacious of life, and are carried 
alive by the Chinese to San Francisco and to Hawaii, where 
they are now naturalized, being known as “ China-fishes.”’ 
Fic. 473 —Channa formosana Jordan & Evermann. Streams of Formosa. 
These fishes have no ‘special organ for holding water on the 
gills, but the gill space may be partly closed by a membrane. 
According to Dr. Gunther, these fishes are ‘able to survive 
drought living in semi-fluid mud or lying in a torpid state 
below the hard-baked crusts of the bottom of a tank from 
which every drop of water has disappeared. Respiration is 
ZY, 
Fig. 474.—Snake-headed China-fish, Ophicephalus barca. India. (After Day.) 
probably entirely suspended during the state of torpidity, but 
whilst the mud is still soft enough to allow them to come to the 
surface, they rise at intervals to take in a quantity of air, by 
means of which their blood is oxygenized. This habit has been 
observed in some species to continue also to the period of the 
year in which the fish lives in normal water, and individuals 
which are kept in a basin and prevented from coming to the 
surface and renewing the air for respiratory purposes are suffo- 
cated. The particular manner in which the accessory branchial 
cavity participates in respiratory functions is not known. It 
is a simple cavity, without an accessory branchial organ, the 
