SECTION OF NAKED-EYED MEDUS&. 123 
brium of Tiaropsis indicans should, in the absence 
of more definite information, refer a distant seat 
of injury to that tract of collected afferent elements 
through which it actually receives the strongest 
stimulation. 
Staurophora Laciniata. 
This is a Medusa about the size of a small saucer 
which responds to stimulation of its marginal 
ganglia, or radial nerve-trunks, by a_ peculiar 
spasmodic movement. This consists in a sudden 
and violent contraction of the entire muscle-sheet, 
the effect of which is to draw together all the 
gelatinous walls of the nectocalyx in a far more 
powerful manner than occurs during ordinary swim- 
ming. In consequence of this spasmodic action 
being so strong, the nectocalyx undergoes a change 
in form of a very marked and distinctive character. 
The corners of the four radial tubes, being occupied 
by comparatively resisting tissue, are not so much 
affected by the spasm as are other parts of the bell; 
and they therefore constitute a sort of framework 
upon which the rest of the bell contracts, the 
whole bell thus assuming the form of an almost 
perfect square, with each side presenting a slight 
concavity inwards. These spasmodic movements, 
however, are quite unmistakable when they occur 
even ina very minute portion of detached tissue ; for, 
however large or small the portion may be, when 
in a spasm it folds upon itself with the characteris- 
tically strong and persistent contraction. I say 
