344 



ZOOLOGY 



SECT. 



the mouth. The end of the body of the Brachiopod with which 

 the peduncle is connected must correspond to the aboral extremity 

 in the Polyzoa, since this represents the part by which the larval 

 Polyzoan becomes fixed, the everted " sucker " of the latter being 

 evidently homologous with the foot-segment of the larval Brachi- 

 opod. The end of the body of the Brachiopod from which the 

 peduncle proceeds is thus the ventral portion. From the position 



FIG. 275. A, Diagrammatic median section of a phylactoltematous Polyzoan. ,>.. anus; 

 ep. epistome ; tp. ca,v. epistome cavity ; funic. funiculus ; gang, ganglion ; int. intestine ; 

 mo. mouth ; neph. nephridium ; us. oesophagus ; st. stomach ; tent, tentacles. B, Diagram- 

 matic median section of Phoronis. nr. nerve-ring. Other letters as in A. (From Korschelt 

 and H eider, after Cori.) 



of the epistome and lophophore, it follows that the dorsal valve 

 of the Brachiopod, being on the same side of the mouth as the 

 epistome, lies on the side of the body corresponding with the anal 

 side of the Polyzoan, though the intestine is bent round in the 

 opposite direction and directed towards the ventral valve. The 

 supra-oesophageal ganglion of the Brachiopod represents the single 

 ganglion of the Polyzoa, though it is subordinate in importance to 



