Volume II. September, l8gg. Number 6. 



ZOOLOGICAL BULLETIN. 



CONTRIBUTIONS ON THE MORPHOLOGY OF 

 THE ACTINOZOA. 



V. THE MESENTERIAL FILAMENTS IN ZOANTHUS SOCIA TUS 



{ELLIS). 



J. PLAYFAIR McMURRICH. 



Several years ago I began a study of the mesenterial 

 filaments of Zoajithus sociatiis (Ellis), taking this form as a 

 representative of the order Zoantheae,and intending, eventually, 

 to extend my observations' to other species and other groups. 

 Various matters have, in the mean time, presented more press- 

 ing claims for attention, and I have so far been unable to carry 

 out my original plan. I have, however, been able to study with 

 considerable thoroughness the filaments of the adult Z. sociatns, 

 and have also secured some data as to their development in bud 

 embryos. I have not been successful in obtaining egg embryos 

 of this species, but have observed certain interesting peculiar- 

 ities in the development of the filaments in some zoanthid 

 larvae whose parentage could not be determined ; some of these 

 I collected myself, whils others I owe to the kindness of Mr. 

 Alexander Agassiz, who obtained them by the surface net in 

 West Indian waters. 



It has seemed to me advisable, notwithstanding the imperfec- 

 tions of my material, to place my observations on record ; the 

 more so that it seems improbable that I shall be able to carry 

 out my original plan of a thorough study of the filaments of 

 the Anthozoa both from the histological and the embryological 

 side. 



