Biomedical Engineering Reference
In-Depth Information
Figure 4.19
E field incident upon sting-ray. Pores are located at the edge
of the ventral (and dorsal) sides of the fin, each leading into the network of
canals and the centrally located ampullae of Lorenzini.
elasmobranch and humans is in the ratio of the constitutive
parameters of the water to that of the fin as compared with the air
to the skinof the human body.
It is noted that rays, which have increased electrosensitivity
above other elasmobranch fish, themselves the most electrosen-
sitive species currently known, have a very distinctive and pro-
nounced geometry that has a larger thinness ratio at the tips than
otherelasmobranches,suchastheshark.Itisalsonotedthatalarge
proportion of the ampullae are located very close to the fin tips,
and coverage is quite extensive to the front of the ray rather than at
the rear (Fig. 4.19), indicative of a forward-seeking electrolocating
predatory function (Murray, 1967). This is also the case for sharks.
The geometric factor for rays and the location of the ampullae
pores near the fin edges lend support to shape being a factor in
electrosensitivity.
