12 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 
Cutting the frenula caused the pedalia to contract but seemed 
not to affect the ability to swim. Comparing the velarium of the 
Cubomeduse with the velum of the Hydromeduse, I recall no 
observations similar to the ones here noted, though it seems that the 
two may have quite similar functions. It seems somewhat probable 
that the velum, and also the velarium, may function in obtaining 
food,—and this besides their function in swimming. Their probable 
function in swimming, as is well known, is evidently to narrow the 
mouth of the bell and thus to cause the water to be forced out in a 
smaller but more rapid stream, giving the animal a steady and more 
prolonged movement through the water at every contraction of the 
bell. In regard to taking food, I observed that a small crustacean, in 
the process of being swallowed by an Olindiad, seemed to be held by 
the velum being firmly contracted about it while the proboscis was 
working itself over the crustacean. It would seem, furthermore, that 
my supposition is supported for Charybdea by the fact that the 
pedalia and tentacles were contracted so as to be brought inside the 
bell when the velarium was cut. The stimulus of cutting the velarium 
may be comparable to a stimulus from some object touching it, and 
thus cause the pedalia and tentacles to come reflexly to aid in 
capturing or holding the object, a fish, crustacean, or such, to be 
captured. 
Pedalia, Interradial Ganglia, Tentacles—Experiments 15, 23, 27-31, 
41b.—When the pedalia were removed, the power of the animal to guide 
itself was completely gone. When one pedalium was cut the others 
contracted, while stroking the outer edge of the pedalia, touching the 
sensory clubs, or sharply pricking the subumbrella, often produced the 
same result. (See also Nerve.) The upper part of the subumbrella 
seemed not so sensitive and more seldom produced the reflex of the 
pedalia, while the base of the stomach did not give it at all. Stroking 
the outer edge of the pedalia of Tripedalia cystophora, the second of the 
two species of Cubomeduse described by Conant, also caused the pedalia 
to be contracted inwards. I may note here that the muscle fibers under 
the ectoderm of the pedalia are specially well developed at and near the 
inner and outer edges, both in Charybdea and Tripedalia. On the 
flattened sides of the pedalia the muscle fibers are fewer. 
When the pedalia were cut off far enough up to remove the 
interradial ganglia, coordination was not affected and the animal 
