PEDICELLINIDJE. 563 



Subclass HOLOBRANCHIA, E. Ray Lankester. 



Group b. ENTOPSOCTA, Nitsche. 



POLYZOA having both the orifices of the alimentary canal 

 within the lophophore ; tentacular sheath wanting; 

 tentacles bilaterally disposed, not retractile ; no peri- 

 visceral cavity *. 



Order PEDICELLINEA. 

 The only order. 



Family I. Pedicellinida. 



POLYPIARIA PEDICKLLTKEA, P. Gervais (1837). 

 Johnston. 



POLYPIDES borne on a retractile peduncle, united in colonies 

 by a creeping stolon. 



WE owe the separation of the Entoprocta from the rest 

 of the Polyzoa as a distinct group to the able German 

 biologist, Nitsche (Zeitsch. wiss. Zool. xx. 1 Heft). 



The chief structural peculiarity which distinguishes 

 them is the position of both the orifices of the alimentary 

 canal within the tentacular wreath ; amongst the ordi- 

 nary Polyzoa (Ectoprocta) the mouth only is surrounded 

 by the tentacles. But associated with this important 



* Amongst the Entoprocta there is no true body-cavity containing a 

 perigastric fluid, as in moat other Polyzoa. Such small space as there is 

 between the inner wall of the rooecium and the alimentary canal is occupied 

 by a more or leas solid parenchymatous tissue. 



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