NEPHRTDTA OF THE ACTINOTROCHA LARVA. 103 



On the Body-Cavities and Nephridia of the 

 Actinotrocha Larva. 



By 



Edwin S. Ooodricli, Wr.A., 



Fellow of Mertoii College, Oxford. 



With Plates 8 and 9. 



On a previous occasion I announced the discovery of soleno- 

 cjtes in the larva of Phoronis (8, p. 499, note 1), and the 

 folloAving paper contains an account of the structure and 

 relations of its excretoi'y organs. Since it is necessary to 

 discuss the nature of the various cavities in the larva in order 

 to thoroughly elucidate the morphological relations of the 

 nephridia, I have gone into some detail on this question, and 

 have illustrated my observations with some diagrammatic re- 

 constructions which will, I hope, render my conclusions clear 

 to the reader. The work is based on the examination of sec- 

 tions of some large Actinotrocha larvae I caught at Trincomalee 

 in 1899, and more especially on the study of some abundant 

 matei'ial I obtained at Faro last July (1902).^ The Cingalese 

 larvte are provided with about thirty-six slender tentacles; 

 the Sicilian larvas when full grown have fourteen tentacles, 

 and probably belong to Phoronis psammophila. 



' I gladly take this opportunity of thanking Professor Dolirn for the loan 

 of apparatus to equip an expedition I undertook from the Zoological Station 

 at Naples, with my friend Dr. Shearer. 



