248
THE BIOLOGY'OF FISHES
,
access to the air, and these are the conditions Which have
made for permanency.
The food in the neighbourhood of -
Ï
the plant—covered coasts is abundant, the supply of oxygen
is plentiful, and it has adapted the simplest of hydrostatic
»
organs in a rough-and-ready manner so as to be able to rise
‘
and descend in the water Without diîculty. From this
group, we may believe, have come all other forms, freshwater shes, the shes of the deep sea, and even the Sharks.
It is at once the most primitive and most modern group of
»shes.
,
'
THE BIOLOGY'OF FISHES
,
access to the air, and these are the conditions Which have
made for permanency.
The food in the neighbourhood of -
Ï
the plant—covered coasts is abundant, the supply of oxygen
is plentiful, and it has adapted the simplest of hydrostatic
»
organs in a rough-and-ready manner so as to be able to rise
‘
and descend in the water Without diîculty. From this
group, we may believe, have come all other forms, freshwater shes, the shes of the deep sea, and even the Sharks.
It is at once the most primitive and most modern group of
»shes.
,
'