Dr. A. KorotnefF o?i Polypavium ambulans. 215 



oesophagus (fig. I.). The relation of the musculature on the 

 directional septa is different from that on other septa — the 

 transverse muscles are directed towards them, the longitudinal 

 from them. Thus, with the directional septa it is exactly as 



Fio-. I. 



Transverse section tliroiigh a young Adamsia diaphana : tmv, mouth- 

 angles; rs, directional septa; Im, longitudinal muscles. (After 

 Hertwig.) 



in the interior chambers of Polyparium^ which is certainly not 

 without significance and needs homologizing. Unfortunately 

 embryology gives us no data for this purpose, because the re- 

 searches of Kowalevsky f and Lacaze-Duthiers \ upon this 

 subject do not thoroughly exhaust the question and are in 

 contradiction to each other. We must therefore treat this 

 question quite a priori. Very probably the directional septa 

 of the Actiniee are the first formed ; they will probably be 

 arcMsepta ; and this postulate is to a certain extent confirmed 

 by the fact that the directional septa undoubtedly correspond 

 to the four longitudinal muscles of the Scyphistoma. In the 



t A. Kowalevsky, '' Unterschungen tiber die Entwicklung der Coelen- 

 teraten," in Nachr. k. Ges. der Freuude der Natui', Anthr. und Ethnoo-r. 

 Moscow, 1873 (in Russian). 



J Lacaze-Duthiers, " Developpement des Coralliaries," in Arch. Zool. 

 exper. et g6n. tome i. 1872. 



