THE ADOLESCENT PERIOD. 89 



the anterior surface of the septum form a follicular epithelial 

 investment. 



T hese knobs, each of which is a solid mass of enlarged epithe- 

 li al cells, gradually increase in size, extending forwards un til 

 t hey ultii ^^H y ""n i | ii " Hn' I'l'lmln l i iij ilh ofthe segmen ts. The 

 cav ities in which they lie, really parts o fthe myoccel (Fig. 41, cm), 

 widen considerably to allow for this increased size, and in speci- 

 me ns of about 15 o r 1 fi mm .l ength become shut off completely fro m 

 t he rest of the myoccel . Eo veri has proposed the t erm gonotome 

 for this portion of the somite, which is specially connected with 

 the reproductive organs, and which is only found in the somites 

 from the tenth to the thirty-fifth or thirty-sixth, in which these 

 organs lie ; he has further directed attention to the fact that the 

 position at which the reproductive organs appear in Amphioxus, 

 close to the line of separation between myoccel and splanch- 

 nocoel, corresponds very nearly to that which they hold, in the 

 earlier stages of their development, in the higher Vertebrates. 



List of the more ifnportant Publications dealing with 

 the development of Amphioxus. 



Boveri, T. : ' Ueber die Bildungsstatte der Geschlechtsdriisen und die Entste- 



hung der Genitalkammern beim Amphioxus.' Anatomischer Anzeiger, 



■vii. 1892. 

 Hatschek, B. : ' Studien iiber Entwicklung des Amphioxus.' Arbeiten aus 



dem Zoologisoben Institute der Universitiit Wien, iv. 1881. 



'Ueber den Schichtenbau von Amphioxus.' Anatomischer Anzeiger, 



iii. 1888. 



' Die Metamerie des Amphioxus und des Ammoccetes.' Verhand- 



lungen der Auatomisohen Gesellschaft, 1892. 

 Kowalevsky, A. . ' Entwiokelungsgeschichte des Amphioxus lanoeolatus.' 



M§moires de I'Aoadlmie Imperiale des Sciences de Saint-P6tersbourg, 



vii° s6rie, tome xi. No. 4. 1867. 



' Weitere Studien iiber die Ent%yicklungsgeschichte des Amphioxus 



lanoeolatus, nebst einem Beitrage zur Homologie des Nerveusystems 



der Wiirmer und Wirbelthiere.' Archiv fiir mikroskopische Anatomie, 



xiii. 1876. 

 Lankester, E. Ray : ' Contributions to the Knowledge of Amphioxus lanoeo- 

 latus.' Quarterly Journal of Microscopical Science, New Series, xxix. 



1889. 

 Lankester, E. Ray, and Willey, A. : ' The Development of the Atrial Chamber 



of Amphioxus.' Quarterly Journal of Microscopical Science, New 



Series, xxxi. 1890. 

 Willey, A. : ' The Later Larval Development of Amphioxus.' Quarterly Journal 



of Microscopical Science, New Series, xxxii. 1891. 

 Wilson, E. B. : ' On Multiple and Partial Development in Amphioxus.' 



Anatomischer Anzeiger, vii. ] 892. 



