302
G . SHELTON
0.1
Water flow (ml/min)
(a)
0
Imposed pressure gradient from buccol to operculor cavities (cm H$)
(b)
Fig. 4. The relationship between water flow over the gills and experimentally
applied pressure gradients. ( a ) In tench ( 4 animals each of approximately l o o p )
which were anesthetized to the point where breathing movements had ceased. The