Meduse of the Philippines and of Torres Straits. 167 
ing expression we might say that the meduse of temperate regions have 
a larger “‘factor of safety’ in respect to temperature. Harvey showed 
that, upon heating, the rate of conduction of the nervous stimulus which 
causes pulsation increases in an arithmetical ratio, so that its ‘‘ curve” 
is a straight line. At from 34° to 39°, however, the curve makes a 
sudden bend downward and the rate declines sharply. This decline 
may be due to the effects of asphyxiation, for Winterstein showed that the 
rate of oxygen consumption in jellyfishes is 3} times as rapid at 30° to 
35° as it isat about 12°C. Thus the oxygen of the sea-water becomes 
insufficient to support the augmented vital activities of the animal. 
The large, rich rosin-brown colored cyaneas of our New England 
coast are not found in the tropics, but closely allied species reappear 
in the south temperate zone, so that somehow they have managed, 
perhaps in the glacial epoch, to cross the warm zone of the tropics. 
Yet another set of forms, which are widely distributed over temperate 
and warm seas, are creatures closely allied to the Dactylometra of the 
southern shore of New England and southward, a jellyfish which may 
be recognized by the reddish brown or purple radial streaks upon the 
umbrella and its long, graceful, folded, curtain-like lips often beauti- 
fully tinged with pink. 
We may distinguish five main divisions or orders of the larger 
jellyfishes or seyphomeduse. 
I. The Carybdeide or Cubomeduse, with bell almost rectangular and 
with flexible tentacles mounted upon the ends of gelatinous wing- 
shaped expansions. They have 4 knob-shaped sense-clubs, which are 
very large and set within niches on the sides of the bell, with the eyes 
all directed inward, apparently to command a view of the mouth. 
These meduse have a marginal diaphragm which partially closes 
the opening to the umbrella cavity. The Carybdeide are confined to 
tropical and warm seas and usually remain upon or near the bottom 
until they become mature, when they often swim to the surface to 
cast out their eggs and sperm. ‘They are usually dull milky-yellow or 
livid in color, and their tentacles sting so sharply that they are com- 
monly called sea-wasps. None are known north of Cape Cod, but 
they are well represented in the tropics throughout the world. 
II. The Stawromeduse are attached forms which do not pulsate. 
The body is pear-shaped or pyramidal and the jellyfish fastens itself to 
sea-weed or rocks by means of a stalk at the aboral end of the body. 
There are usually 8 clusters of knobbed tentacles which are developed 
at the pointed ends of 8 marginal lobes, and 8 large ‘‘anchors” or 
sucker-like clubs upon the margin may alternate with the tentacles. 
These forms are confined to cold seas and are known from the Arctic and 
Antarctic Oceans, although they have never been found in the tropics. 
III. The Coronate are usually deep-sea forms distinguished by their 
peculiar dark purple or reddish-brown color, which is so characteristic 
