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has proved that the small animals which form these branches 

 and frills are very differently, and much more highly, organized 

 than the coral polypes. They have a noose-shaped intestine, are 

 provided with a mouth, fringed with ciliated feelers, and have 

 a separate anus: muscles and nerves are also found. All these are 

 things which the polyps do not possess, and their entirely different 

 manner of development also teaches us that these two groups, 

 in spite of their outward" resemblance , are not in the least 

 connected. The Bryozoa are found in all seas, and reveal an 

 astonishing wealth of forms, the knowledge of which is opened 

 to us by an extensive literature relating to this group. Their 

 division into different kinds according to the delicate microscopic 

 details of their shells is the life's occupation of numbers of 

 zoologists, and lately it has been tried, by the study of their 

 development, to lift the veil that conceals their origin and re- 

 lation to other animal forms. 



Crustacea or Crabs, Lobsters and Shrimps. 



These animals form a very peculiar and strictly denned group. 

 Contrasted with the quiet dreamy lives of the zoophytes and 

 annelids, the monotonous motions of the apathetic fishes, or the 

 lazy rnolliisks and sea-urchins, the active and often comical mo- 

 vements of the different kinds of crabs are very attractive, and 

 we soon discover that the mental qualities of these creatures 

 far exceed those of most other marine animals. We are thinking 

 chiefly of the short tailed crabs and similar animals, which are 

 to be found in one of the smaller tanks; but, as the non-scien- 

 tific visitor is usually best acquainted with the lobster, we will 

 begin with the latter, and from it try to enable him to under- 

 stand the remaining forms of Crustacea. 



The Lobster, (Homarus marinus) is, on the whole, an 

 enlarged copy of the fresh-water crayfish, and the visitor will 

 easily learn, from examining the large examples in the Aquarium, 

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

 vided into a segmented fore-part, covered by a single carapace or 

 upper shell; a head and breast piece and a hinder part composed of 

 jointed rings, forming the "tail" of the lobster, and ending in a 

 fin composed of broad flat plates. In the front pait of the head 

 and breast-piece are the eyes, two pair of antennae or feelers, 

 and a little farther behind and below, the mouth, consisting 

 of six pairs of jaws , the three front pairs being distinguished 

 as upper and under jaws , while the hinder ones are called 



