66 CRISTATELLA MUCEDO. 



future observation. Placing it in a zoophyte trough, I was 

 rewarded by a magnificent sight of snowy crests and waving 

 tentacles, which afforded me many a pleasant hour in watching its 

 movements and learning its history. It was purely an accidental 

 capture ; but I felt more convinced than before that, live where 

 we may, we have lying all around us ample resources for 

 microscopical study : — 



"Where the pool 



Stands mantled o'er with green — invisible 



Amid the floating verdure millions stray ; 



These concealed, 



By the kind art of forming Heaven, escape 



The grosser eyes of man." 



The poet, with his " grosser " allusions, has committed whole- 

 sale slaughter among microscopists. Some unaided eyes, no 

 doubt, see a great deal more in Nature's cryptic stores than even 

 some microscopical observers ; but when, in addition to the 

 trained organs of natural vision, we possess, and can skilfully use, 

 a phalanx of delicately-formed glasses to reveal the beauties of 

 an unseen world, full of Nature's artistic embellishment, which of 

 us would not feel traduced by the " grosser " hints of the poet's 

 muse? 



Cristatella mucedo belongs to the large sub-kingdom of the 

 MoLLUSCA, of which there are two divisions : — the Mollusca 

 proper, and the Molluscoida. In the former division the 

 nervous system consists of three principal pairs of ganglia, with a 

 well-developed heart of at least two chambers, as,/.^., in the class 

 Gasteropoda, which includes the Snail and the Whelk. Crista- 

 tella, however, belongs to the Molluscoida, in which the heart is 

 either imperfect or absent, and in which the nervous system 

 consists either of a single ganglion, or of one pair with accessory 

 ganglia. The Molluscoida until lately were divided into three 

 classes: — the Polyzoa or Bryozoa ; the Ttmicata or Ascidioida; 

 and the Brachiopoda. The latter two are always marine, while 

 the Polyzoa comprise both marine and fresh-water species ; and 

 Cristatella mucedo, with which we are now concerned; is one of 

 the latter. 



