6 THE AMPHIOXUS. 



ever, through its "being written in Russian, are but 

 little known to the zoologists of other countries. The 

 author therefore published in German the results 

 arrived at in this work, among the Archives of Micro- 

 scopic Anatomy in 187G. 1 These later investigations 

 make us acquainted with the formation of the mesc- 

 blast, the development of the notochord from the 

 hypoblast, the details of the development of the neural 

 canal, and the fate of the mouth of the gastrula 

 (neurenteric canal). 



This is not the place to give an exhaustive account 

 of Kowalevsky's well-known results. I will however, 

 in each separate section of my work, briefly refer to 

 his observations, and allude to different results yielded 

 by my own investigations. 



EEMAEKS UPON THE SPECIES EXAMINED. 



IT is not my intention to give here any general 

 answer to the question as to how far systematists 

 are justified in their classification of the various 

 species of the Ampliioxus. I will merely show what 



1 A. Kowalevsky, " We it ere Studien fiber die Entwicklungs- 

 geschiclite des Ampliioxns lanceolatus, nebst ei'nem Beitrage zur 

 Homologie des Nervensysfcems der Wiirmer und Wirbelthiere," 

 Arch. f. mikr. Anat., Bd. xiii. 1S7G. 



