352 FISHES. [Chap. X. 
and by degrees their whole bodies, in the mud ; sinking 
to a depth at which they find sufficient moisture to pre- 
serve life in a state of lethargy long after the bed of the 
tank has been consolidated by the intense heat of the 
sun. It is possible, too, that the cracks which reticulate 
the surface may admit air to some extent to sustain their 
faint respiration. 
The same thing takes place in other tropical regions, 
subject to vicissitudes of drought and moisture. The 
Protopterus 1 , which inhabits the Grambia (and which 
though demonstrated by Professor Owen to possess all 
the essential organisation of fishes, is nevertheless pro- 
vided with true lungs), is accustomed in the dry season, 
when the river retires into its channel, to bury itself to 
the depth of twelve or sixteen inches in the indurated 
mud of the banks, and to remain in a state of torpor till 
the rising of the stream after the rains enables it to re- 
sume its active habits. At this period the natives of the 
Gambia, like those of Ceylon, resort to the river, and 
secure the fish in considerable numbers as they flounder 
in the still shallow water. A parallel instance occurs 
in Abyssinia in relation to the fish of the Mareb, one of 
the sources of the Nile, the waters of which are partially 
absorbed in traversing the plains of Taka. During the 
summer its bed is dry, and in the slime at the depth of 
more than six feet is found a species of fish without 
scales, different from any known to inhabit the Mle. 2 
1 Lepidosiren annectans, Owen, ritier presomptif du royaume 
See Linn. Trans. 1839. d'Alouah, m'a assure que Ton 
2 This statement will be found trouve, dans la vase qui couvre le 
in Quatremere's Memoir es sur fond cLe eette riviere, un grand 
VEgypte, torn. i. p. 17, on the poisson sans ecailles, qui ne res- 
authority of Abdullah ben Ahmed semble en rien aux poissons du 
ben Solaim Assouany, in his Nil, et que, pom- 1' avoir, il faut 
History of Nubia, " Simon, he- creuser a une toise et plus de pro- 
