572 



POLYZOA. 



Te 



Phylactolaemata. In both there is a horseshoe-shaped lophophore, an epistome r 

 a division of the body-cavity by a septum into a small part at the oral end, and 

 the main part around the alimentary canal, and the presence of a pair of very 

 similar nephridia. Of these resemblances the first two 

 are not important, while the third and fourth concern 

 doubtful points of anatomy. Against this comparison 

 is to be set the development. In Phoronis the line 

 between the mouth and anus is dorsal, and would 

 contain, if it still existed, the preoral lobe of the larva. 

 In the Ectoprocta, on the other hand, the line between 

 the mouth and anus is ventral, though this would 

 possibly be disputed by some zoologists (see p. 563) ; 

 while in the Entoprocta the oro-anal surface is unques- 

 tionably ventral, the preoral lobe and its sense organ 

 belonging demonstrably to the surface between the anus, 

 and the attachment of the adult (Fig. 455). 



The Entoprocta are, with the exception of 

 Urnatella, marine animals. Pedicellina is 

 stalked and colonial. Loxosoma is solitary; 

 the buds, which are formed, separating from 

 their parent. Loxosoma is generally a com- 

 mensal. 



Fam. 1. Loxosomatidae. Solitary forms budding 

 from the body ; the buds separate from the parent. 

 Loxosoma Kef., L. phascolosomatum at the end of the 

 body of Phascolosoma, L. (Cyclatella) annelidicola, on 

 the Maldanidae, etc. 



Fam. 2. Pedicellinidae. Stalked, colonial forms, 

 attached to a creeping stolon ; budding at the growing 

 point of the stolon. Pedicellina M. Sars. 



Fam. 3. Urnatellidae. Stalked colonial, fresh-water 

 forms, N. America. Urnatella Leidy. 



FIG. 456. Pedicellina, 

 echinata. Te tentacular 

 crown ; mouth ; Md 

 alimentary canal ; A 

 anus ; Or ovary; G gan- 

 glion. (From Glaus.) 



