Fig. 4. (A) The relationship between angular size (ßR) and
Yforward at various theoretical values of
Xlateral. The graph is valid for all speeds, because
angular size is not affected by current speed (Uc). Any
given value of ßR is reached at decreasing values of
Yforward as Xlateral increases. (B)
The relationship between loom 
R and
Yforward (the particle distance upstream at the time of
TR), at various theoretical values of
Xlateral, at the intermediate current speed used in
darkened conditions. At Xlateral=0, R
is always highest. Horizontal line represents the average experimental values
of R found in darkened conditions at intermediate
Uc. R is reached at smaller values of
Yforward as Xlateral values increase.
(C) The relationship between angular velocity 
R and
Yforward at various theoretical values of
Xlateral, at the intermediate current speed used for
semi-transparent Artemia. At Xlateral=0,
R would be equal to zero and it is not represented.
Horizontal line represents the average experimental values of
R found for semi-transparent Artemia at
intermediate Uc. Average R is reached at
increasing values of Yforward as
Xlateral values increase.