The mesenterial Filaments of the Alcyonaria. 9 



bave discovered, in Pemiatula and Virgularia, foreigü bodies, such as 

 diatoms, actually embedded in thc filaments i. Altbougb they do not 

 State in wliicb filaments these bodies were found, it is clear from their 

 figures that it was in the entodermic filaments. This indicated that 

 duriug digestion solid matters are takeu bodily into the filaments, and 

 are probably actually engulphed by the cells ^moeJa-fashion, as in 

 many other Coelenterata. This very iraportant Observation I can fully 

 confirm in Älcyonium^ Paralcyonimn and Funieulina. where diatoms 

 and other solid foreign bodies may with the greatest clearness be seen 

 enclosed in vacuoles within the entodermic filaments. In fig. 12 [Par- 

 akijoumm) we see a diatom and three other foreign bodies entirely 

 imbedded in the substance of the filament , and similar bodies are seen 

 at V in fig. 11 and 13. It is impossible to determine whether these bod- 

 ies lic within or only between the cells, but the former seems from ana- 

 logy ])robable In Paralcyomum these bodies are sometimes very abun- 

 dant, but they are always confined, sofar as 1 have observ- 

 ed, to thc entodermic filaments and never are found cither 

 in the dorsal filaments or in the general entoderm cover- 

 ing the septa and tlie body-wall. 



From these factsit seems very probable that the digestive 

 functions are performed by the entodermic filaments 

 alone and never by the cctodermic filaments or the general 

 entoderm. This conclusion accords entirely with the histological 

 structurc of these organs, and so far as the ectodermic filaments are 

 concerned, is what we might expcct from their embryological origin. 

 The large granular cells, usually dcscribed as glandulär, which form 

 the great mass of the entodermic filaments , I am inclined to regard as 

 cells which act like so many Amoebae, taking solid particles into their 

 interior and there digesting them. In the ectodermic filaments such 

 cells do not exist; and although it is difficult to prove a negative in 

 such matters, the structure of the ciliated cells of which they are com- 

 posed (see part II) is such as to indicate anything rather than a di- 

 gestive function. The same is true of the general entoderm covering 

 the septa and the body-walls. As I have said this entoderm has usually 

 the form of a pavement-epithelium (compare figs. 5 , 10, 11,12). In 

 some genera this epithelium is exceediugly thin, as in Alcyonmm and 

 Paralcyomum. In others it is thicker , either everywhere or in parts, 

 especially in the upper part of the body-wall, and in some forms it be- 



Keport on the Oban Pennatulida, Birmingham, 1882. 



