PARKER: LONGITUDINAL FISSION IN METRIDIUM MARGINATUM. 55 



Thorell, T. 



'59. Oni den inre byggnaden af Actinia plumosa Mull. Ofversigt af Kougl. 

 Vetenskaps-Akademiens Forhandliugar. Vol. XV. 1858, pp. 7—25, 

 Tab. I. 



Torrey, H. B. 



'98. Observations on Monogenesis in Metridium. Proceed. California Acad. 

 Sc, 3d Ser., Zoology, Vol. I. pp. 345-360, PL XXI. 



Wilson, H. V. 



'89. On the Occasional Presence of a Mouth and Anus iu the Actinozoa. 

 Johns Hopkins University Circulars. Vol. VIII. pp. 37, 3S. 



