flagellum, and soon the polypide grows inside, the stomach and 

 tentacles arise, and finally the polypide is formed. 



In conclusion, the Polyzoa increase (a) by budding, (b) by 

 normal eggs and winter eggs. In reproducing from eggs the 

 young passes through : 



1. Morula state. 



2. Trochosphere, much as in certain worms and mollusks, attain- 

 ing the 



3. Adult condition (zocecium). 



Claparede. Beitraj 



VII. THE BRACHIOPODA. 



While the Brachiopods have been regarded by many as closely 

 related to the Polyzoa, there are many features, as insisted on by 

 Prof. Morse, which closely ally them to the Clnetopod worms. In 

 his treatise "On the systematic Position of the Brachiopoda," 1 

 Morse has given conclusive reasons for removing them from the 

 mollusks and placing them among the worms, and even, in his 

 opinion, among the Chaetopods, the highest division of worms. 

 He thus, after giving the anatomical facts in his view sustaining 

 his position, concludes that ancient Chaetopod worms culminated 

 in two parallel lines, on the one hand, in the Brachiopods, and 

 on the other, in the fixed and highly cephalized Chffitopods. 



On the other hand Mr. A. Agassiz, swayed by their relationship 

 to the Polyzoa, remarks that "the close relationship between 

 Brachiopods and Bryozoa cannot be more fully demonstrated than 

 by the beautiful drawings on PI. v., of Kowalevsky's history of 

 Thecidium. We shall now have at least a rational explanation ol 

 the homologies of Brachiopods, and the transition between -^h 

 types as Pedicellina to Membranipora and other incrusling V>*y- 

 ozoa, is readily explained from the embryology of Theckbmm^In 



