CEPHALOCHORDA. 7 



The vascular system of Amphioxus appears at about the same 

 time as the first visceral clefts. 



Bibliography. 



(i) A. Kowalevsky. "Entwicklungsgeschiclite des Amphioxus lanceolatns." 

 Mem, Acad. Imper. des Sciences de St Petershourg, Series vii. Tom. xi. 1867. 



(2) A. Kowalevsky, "Weitere Studien iiber die Entwicklungsgeschichte des 

 Amphioxus lanceolatus." Archiv f. mikr. Anat., Vol. xiii. 1877. 



(3) Leuckart u. Pagenstecher. " Untersuchungen iiber niedere Seethiere." 

 Mailer's Archiv, 1858. 



(4) Max Schultze. "Beobachtung junger Exemplare von Amphioxus." Zeit. 

 f. wiss. Zool., Bd. in. 1851. 



(5) A. M. Marshall. "On the mode of Oviposition of Amphioxus." Jour, of 

 Anai. and Fhys., Vol. x. 1876. 



