CLASSIFICATION OF THE ANIMAL KINGDOM. 51 



the latter genus — the Tubiporidce, we find animals which, although they 

 live in society, do not seem to he organically united; they have, moreover, 

 the power of protruding themselves from the mouths of their tubes, and 

 their ovaries are more highly developed. 



Next come the Actina, composed of a fleshy substance, attached by one 

 end to a rock, and having numerous tentacula at the other, with which 

 they catch their prey. They can detach themselves from their fixed position 

 at pleasure, and move along the rocks, or render themselves buoyant by 

 distension. Their stomachs are simple bags within the body, and have 

 only one orifice, the mouth. Their mode of respiration is by drawing 

 water through the tentacula, which are perforated, into a series of chambers 

 which communicate with one another, between the digestive bag and the 

 outer integument of the animal. Their organs of reproduction are more 

 highly developed than [those preceding; their eggs, which are very abundant, 

 are secreted by peculiar membranes situate within the chambers before 

 spoken of, and the young escape by a minute aperture at the base of the 

 stomach. The Anemones are likewise produceable by mechanical division. 

 As to their nervous system, some authors seem to think that they have 

 discovered a few delicate threads in different parts of the body, but these 

 surmises are not free from doubt. 



The next tribe of Polyps mentioned are unciliated gregarious animals 

 living in horny tubes, those having cilia — the Bryozoa — being of a much 

 higher organization, as will presently appear. These Zoophytes are com- 

 mon on our own coasts, and are often taken by the ignorant for sea- 

 weeds. They possess a sort of circulation very much like that found in 

 some plants. The tentacles of these animals, when stretched out, are 

 seen to be studded with minute tubercules, but are never provided with 

 cilia. Their stomach is a digestive sac filled with granular matter, and 

 they are reproduced in different ways; by cuttings, as in plants, by the 

 formation of new branches, and by gemmules capable of locomotion by 

 means of cilia. The gemmules spring from cells produced at certain 

 periods of the year on the stem of the Zoophyte, and are termed vesicles; 

 they are larger than the common cells, and fall off when they have fulfilled 

 their functions. 



We now leave the Polyps and come to the next class, the Polygastrica, 

 or Infusoria Animalcula, animals of the minutest kind, and the very atoms 

 of creation, yet how wonderful in their structure! This family is divided 

 into two groups, one having a soft body, and the other covered with a 

 delicate transparent shell, the former termed iSuda, and the latter Loricata 

 Animalcula. Some of the soft-bodied ones are perfect harlequins; they 

 can contract and elongate themselves at pleasure, sometimes appearing 

 round, at others linear, and they assume every intermediate variety of 



