128 CELENTERATA. 
the body. It is perfectly transparent except for the four 
gonads which are of a beautiful violet hue. 
It differs in shape from the medusoids of Ode/a, for 
it is flat, not bell-shaped. However, the general principles 
of its construction are in many respects similar. 
It is axially symmetrical and tetramerous, ze, 
the peripheral parts are arranged in fours. The 
mouth is four-cornered and opens ona short manubrium. It 
is surrounded by four large oral tentacles which correspond 
to the four corners of the mouth and are jer-radial. 
The disc or umbrella is almost circular but slightly divided 
External 
Features. 
Fig. 60.—ORAL VIEW OF AURELIA AURITA x $. (Ad nat.) 
Per-radial Canal. Tentaculocyst. Ad-radial Canal. 
Inter-radial _ 
Canal. 
Oral 
Tentacles. 
genital Pit, 
Mouth. 
into eight lobes, the indentations between them being at the 
four per-radii and the four zzfev-raditz. In each depression 
or indentation there is situated a sense-organ or fentaculocyst 
covered by a hood and having a pair of small processes or 
lappets, one on each side. The whole border of the disc is 
fringed by a great number of small tentacles and there is no 
velum. 
