HYDROZOA. 



0< 



liii-irer aud commoiior kinds of Jelly- Fi.sh or Sca-Nuttles. A brief 

 accouut is ,ij:ivL'ii below of Aurelia unrita* (Model and sjK-eimenH ' 1 

 in Case 3), whose phantom disks are so often seen in summer 

 time slowly swimmiutr below the surface. In the centre of the 

 shallow umbrella are four pur[)le horsesh(»e-sliai»ed or circular 

 generative masses ; in the centre of the under surface is the 

 manubrium prolon<jred into four arms ; the maririn of the und»ri-lla 

 is provided with a fringe of very short line tentacles, the uniformity 



Fig. 20. 



Carmarina hitstata,one of the Truchomeduxx. (After Haeckel, and from Kncve. 



Britannicii.) 



of the fringe being l)rokeu by eight notches, each containing 

 a teutaculo-cyst ; each of tlie latter (Fig. 21) is covered by a _ Tuso a. 

 pair of minute lappets, hence Medusre of this ty])e were called ^ "'■'>^''' !' 

 Covered-Eyed ; while those of the Ilydronicdusan tyjK', being 

 without lappets, were called Naked- Kyed. 



The thickness of the umbrella is traversed by a .system of simple 

 and brauclied canals, which pass from tlu' central stomach to a 

 circular canal running round the margin of the uud)relln. Pro- 



