CYDIPPE. 131 
a number of free-swimming forms, called Zphyre. An Ephyra has 
eight long arms, Zer-vadial and tnter-radial, down which are produced 
the eight primary canals. The end of each arm is bifid, forming the 
two lappets, between which is the tentaculocyst. By differential growth 
the Zfhyra fills up the ad-radial depressions and becomes a young 
Aurelia. The teeniole disappear, leaving only the gastric filaments, 
whilst the bases of the septal funnels form the sub-genital pits. 
Here we have a metagenesis, as in Ode/da, but the scyphula does not 
form a true colony, abbreviating this stage by rapid transverse fission. 
VI.—CYDIPPE. 
PHYLUM Ca:LENTERATA. 
Crass CTENOPHORA. 
Cydippe is one of the most beautiful little organisms to be found in 
the sea. It is pelagic and appears like an almost spherical transparent 
ball of glass, usually about one-half inch in diameter. It feeds 
voraciously on pelagic organisms, ¢.g., young fish. When alive it moves 
Fig. 65.—CybIPPE PLUMOSA. 
(After Cun.) 
Tentacle with 2 Shy 
Adhesive Cells, < 46 
Row of Combs, 
Longitudinal Canal. 
with ceaseless activity and is iridescent with rainbow (interference) 
colours. One axis is slightly longer than the other, at one end of which 
(oral) is the mouth ; at the aboral end is a sense-organ. From oral 
to aboral end there run eight meridional rows of rapidly moving coméds 
which are formed by a row of cilia fused at their base. All the combs 
strike in an oral-aboral direction and the result is a steady, fairly rapid 
movement forward. Two long tentacles trail behind the animal and 
give stability to its movements. They bear small branches which are 
covered with spirally stalked adheszve cells. The tentacles are very 
sensitive and can be completely retracted within a pair of sheaths 
or pockets. The mouth leads into an ectodermal gwd/et which 
passes into-a stomach. The stomach tapers towards the aboral 
end and branches into four ducts which open symmetrically round 
the aboral sense-organ. 
