SEA-SNAILS AND SEA-SLUGS. 22Q 



as it may change its diet. Scientifically these papillae are 

 termed cerata. 



The last of our Sea-slugs does not belong to the Nudibran- 

 chiata, for its branchiae are concealed, and it possesses a shell 

 a thin, flexible, translucent, convex plate, that covers the 



SEA-HARE. 



branchial plume, and is itself covered by the mantle. My 

 first Sea Hare (Aplysia depilans], was taken in ignorance. A 

 hurried glance at a globular mass of purple-brown jelly, among 

 some small weeds, as I was hunting for anemones, assured 

 me I had something new to me, and I put it down at the 

 moment as a colony of compound ascidians ; but on putting 



