68 Part second. 



The Annelids have lately become a special field of study among 

 zoologists, since their comparative anatomy has revealed features which 

 support the theory of their relationship to the Vertebrates. At present 

 a lively scientific controversy is being carried on with regard to this 

 moot point. 



POLYZOA or BRY0ZOA. 



The name Polyzoa^ i. e. multiple animals, was given to this group 

 from the fact that they live in large colonies, like the corals. By the 

 German school they are always called Bryozoa or moss-animals, a name 

 which arose from the moss-like or coral-like growths which these colo- 

 nies form. 



The graceful net-like frill of Betepora (Fig. 1 1 6), or the branching 

 stem of Myriozoum (Fig. 117), may easily be mistaken for corals, to 

 which, however, they are by no means allied. Careful observation has 

 shown that the little animals which form these growths, and live toge- 

 ther in colonies, are very different from, 'and more highly organized than, 

 the polypes of a coral. 



The Polyzoa are widely distributed in all seas and present a won- 

 derful variety of forms. A kind very common on the British coast and 

 well known to all visitors to the sea-side is the leaf-like growth of 

 Flustra, the sea-mat, the colour and texture of whitey-brown paper. 



CRABS, LOBSTERS, SHRIMPS, BARNACLES etc. 

 (CRUSTACEA). 



These animals form a peculiar and very strictly defined group. 

 Contrasted with the quiet and dreamy lives of the brightly coloured 

 corals and the annelids, with the monotonous movements of the apathetic 

 fishes, and with the lazy mollusks and echinoderms, the active and often 

 comical movements of the different kinds of Crabs are very attractive; 

 and we soon discover that the mental faculties of these creatures far 

 exceed those of most other marine animals. In making this statement 

 we have in mind chiefly the short-tailed Crabs and their allies, which 

 are found in tank Nr. 23; but as most people are better acquainted 

 with the long-tailed Lobster, we begin with the latter, and try to explain 

 the other forms by comparison with the better-known animal. 



The Lobster, Homarus vulgaris (Fig. 163), is, on the whole, an 

 enlarged copy of the fresh-water crayfish; and visitors will easily recog- 

 nize, from examining the large specimens in the Aquarium (tank Nr. b), 

 what are the principal features of its organisation. The body is divided 

 into an anterior part, consisting of head and chest, which is really joint- 

 ed but covered on the upper surface by an unjointed shell (carapace)', 

 and a posterior part, composed of a number of rings forming the "tail" 

 of the Lobster, which terminates in a fin composed of broad, flat plates. 

 The anterior portion bears the stalked eyes and two pairs of antennae 

 or feelers, one pair very long, the other shorter and forked. Behind 

 these, and on the under surface is the mouth, furnished with six pairs 



