BRYOZOA. 



1-0 



I > 



into two lobes so as to have a horse-shoe shape (Lop/iopoda, fig. 54."),. 

 and its margins are produced into a number of richly ciliated ten- 

 tacles. The tentacles are simply hollow processes of the body wall ; 

 they are provided with longitudinal muscles, and their cavity com- 

 municates with the body cavity, from which they are filled with 

 blood. They serve both for procuring food (setting up by means of 

 their cilia whirlpools in the water) and for respiration. 



,- 



The digestive organs lie freely in the body 

 cavity, and are attached to the integument by the 

 Mj-called funiculus and by bundles of muscles. 

 The body and tentacular apparatus has been in- 

 correctly regarded as a kind of individual, and 

 opposed to the cell or Cystid, in which it is placed, 

 as the Polypid. The mouth is placed in the centre 

 of the circular or horse-shoe shaped lophopore, and 

 a moveable epiglottis-like process, known as the 

 epistome, often projects over it. The alimentary 

 canal is bent on itself, and consists of (1) an 

 elongated ciliated oesophagus often dilated to a 

 muscular pharynx ; (2) a spacious stomach, with 

 a blind backward prolongation, the hind end of 

 which is attached to the body-wall by a cord 

 (funiculus), and (3) a narrow intestine, which is 

 bent up nearly parallel with the pharynx and is 

 directed forwards. The intestine opens by the 

 dorsally-p laced anus, near but usually outside the 

 buccal disc (Ectoprocta, tig. 545). In a few forms 

 the anus is within the circle of tentacles (Endo- 

 in-octa), e.g.. Pedicellina and Loxosoma (fig. 546). 



' FIG. 546. /'. ' ' 



Heart and vascular system are absent. The ,,!,,, ,*,. ?-,, tentaou- 

 blood fills the whole body cavity, through which ^r crown ; 0, mouth ; 



MI), alimentary canal; 



it is circulated chiefly by the cilia of the body- A, anus ; G, ganglion; 

 wall. The whole surface of the anterior protrusible 

 part of the body, and especially of the tentacles, serves as a 

 respiratory organ. The ciliated canal of the Endoprocta is to be 

 regarded as a kidney. 



The nervous system consists of a ganglion placed on the oeso- 

 phagus between the mouth and the anus. This ganglion in the 

 Lophopoda is contained in the cavity of the lophophore, and is 

 attached to the oesophagus by a delicate circum-cesophageal ring ; it 

 sends oft' numerous nerves to the tentacles and oesophagus. Accord- 



