THE ASCIDIANS. 



247 



the marine tanks of the Crystal Palace, Brighton, 

 and elsewhere. They are pretty objects, increasing 

 at an abundant rate. The embryos of some of them 

 (notably the Cynthia, commonly known as the " cur- 

 rant squirter ") are free-swimmers, and have a peculiar 



Fig. 179. 



Fig. 1 80. 



Cynthia, and its Tadpole. 



Ascidia mentula. 



tadpole-like appearance. Among fishermen all the 

 ascidians go by the popular name of "sea-squirts," 

 from the ease with which they can eject a jet of 

 water when their leathery outer tunic contracts ; 

 hence their name of Tunicata. These peculiar, and 

 to the philosophical naturalist most interesting, 



