ACALEPHJ5. 
245 
and a terminal aerial vesicule. It is much the same in the 1 rayse 
or Diphydse. In this family a great number of natatory vesicles are 
connected with the terminal aerial vesicle, as in Fig. 101, Fray a diphys. 
This species is widely diffused in the sea which bathes the Nicean 
coast, hut it is very difficult to procure perfect specimens. M. Yogt 
Fig. 101. Praya diphys (Blainville). 
f °nnd fragments more than three feet long which swam on the 
surface, and was in its state of contraction not more than a finger s 
length. This species has been met with at Porta della Praya and at 
8an Yago, one of the Cape de Verde islands. 
The colony of the Praya presents two great locomotive bell-shaped 
Masses, between which the common trunk is suspended, and to which 
it can retire. This cylindrical trunk, which is thin and transparent, 
