382 WILLIAM A. HAS WELL. 



Annulata did not result from the modification of a chain of 

 zooids developed by serial budding as supposed by Haeckel^ 

 Hatschek, and others ; but by the dividing up of the body of 

 an elongate animal into a series of similar parts (Laug, 

 Meyer, Eisig). In whatever manner the mesoderm bands, 

 the mesoderm somites, and the resulting secondary meso- 

 dermal structures may have first originated, whether by 

 modification of reproductive cells as supposed by E. Meyer, 

 or by the proliferation of primitive mesodermal elements, it 

 appears probable that the various organs passed through a 

 condition of pseudo-metamerism, which became converted into 

 nascent true metamerism as the ciliary mode of locomotion 

 became completely given up, and a creepiug mode fully 

 adopted. 



LiTERATUEE. 



1. Beneden, p. J. Van. — " Note sur une larve d' Annelids," etc., ' Bull. 



Acad. Roy. Belg.,' t. xx. 



2. Beneden, P. J. Van. — " Histoire naturelle d'un Animal nouveau de- 



signe sous le nom d'Histriobdella," ' Bull. Acad. Hoy. Belg.' (2), 

 tome V. 



3. Dklage, Yves, and Herouaed, Edgakd. — ' Traite de Zoologie Concrete,' 



tome V, '• Les Veimidiens," 1897. 



4. Eisig, Hugo. — " Die Capitelliden," ' Fauna u. Flora des Golfes v. 



Neapel.' 



5. Eisig, Hugo. — " Die Entwickelungsgeschicble der Capitelliden," 'Mittli. 



Z. Stat. Neapel,' Bd. xiii, 1898. 



6. FtETTiNGER, ALEXANDER. — " Reclierclics sur I'organisation d'Histriob- 



della bomari, P. J. Van Beneden, rapportee aux Arcbiannelides," 

 'Arcb. Biol.,' tome v, 1884. 



7. Fraipont, Julien. — " Recbercbes sur le systeme nerveux central et 



peripberique des Arcbiannelides (Protodrilus et Polygordius), et du 

 Saccocirrus papillocercus," 'Arcb. Biol.,' t. v, 1884. 



8. Fraipont, Julien. — " Le genre Polygordius," 'Fauna ,u. Flora des 



Golfes V. Neapel,' 1887- 



