POLYZOA. 



609 



At one end there is a rounded head, and at the other a forked tail. 

 The burrow which the creature forms is either wholly or partially 

 lined with shell, and it is worthy of notice that the Ship-worm and 

 its mode of burrowing gave Sir I. Brunei the idea of the Thames Tunnel. 



POLYZOA. 



The very remarkable beings which now come before our notice are 

 appropriately termed Polyzoa, from two Greek words signifying " many 

 animals,'* because a 

 large number of in- 

 dividuals are massed 

 together in groups 

 of various forms and 

 textures. 



The true animal 

 nature of these and 

 many other beings 

 which had been for- 

 merly classed among 

 the vegetables was at 

 length fairly proved 

 by the researches of 

 two eminent men, 

 Trembley and Ellis, 



the latter of whom ^' ^<*'^«''<^«^^« lorica. B. Catenieella hastata. C. Cateni- 



, , . , ce^^a corniita. D. Calpidinm ornatum. E. Saliconiaria 



may lay claim to the fardminoides. F. Celhdaria Peachii. G. Menipea Fu- 



honor of having pro- fl"'*"*^** (mouth of a cell). 



duced the best and most comprehensive work of his time. 



Fig. A is an example of one of these beings, the Little Chain, or 

 Breastplate, one of those creatures that are so plentiful in the sea, 

 and are popularly called zoophytes. This figure is of the natural size ; 

 but in order to show the peculiarities of structure, two examples of 

 species belonging to the same genus are given as they appear when 

 considerably magnified. Fig. B is the Catenieella hastata^ wherein are 

 seen the shape of the cells, the form of their mouths, the method in 

 which they give out their branches, and the peculiar organs called 

 technically " avicularia " and " vibracula," the former being processes 

 that in many species bear an almost absurdly close resemblance to the 

 heads of birds ; and the latter, curious hair-like projections which move 

 regularly backward and forward as if impelled by machinery. 



The members of the present genus are found most commonly in the 

 Australian seas, seldom in the southern hemisphere, while in the north- 

 ern hemisphere they are almost entirely unknown. Many specimens 



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