452 SCIENCE PROGRESS. 



in both the filaments and the general endoderm ? Upon 

 these points there is conflicting evidence. Wilson and 

 others found certain diatoms and other foreign bodies em- 

 bedded in the epithelium of the filaments, and failed to find 

 them in the endoderm cells of the mesenteries and body 

 wall, and consequently the former came to the conclusion 

 that probably "the digestive functions are performed by 

 the entodermic filaments alone, and never by the ectodermic 

 filaments or the general entoderm ". 



A little consideration, however, would have led the 

 American observer, one cannot help thinking, to a different 

 conclusion ; for he himself and the writer of the present 

 article, working quite independently of one another, dis- 

 covered that a regular circulation of the fluids of the 

 ccelenteron in Alcyonaria is effected by the long cilia of 

 the groove on the ventral side of the stomodaeum pro- 

 ducing a current from without inwards on the one side, and 

 by the cilia of the dorsal or ectodermic filaments producing 

 a current in a reverse direction on the opposite side of the 

 ccelenteron. 



Now such a current, constantly at work, must im- 

 mediately drive the fluid products of digestion away from 

 the region of the filaments, and they would consequently 

 be entirely lost to the animal unless they were absorbed 

 by the general endoderm. Moreover, it is difficult to 

 understand how the lower parts of a massive colony such 

 as Alcyonium could receive any nourishment at all if the 

 absorption of the food occurs only in the filaments, unless 

 indeed we suppose that nourishment may be handed on 

 from cell to cell for two or three feet of endoderm. 



Some recent investigations of Willem on the digestion 

 of sea-anemones leads us to the conclusion that the absorp- 

 tion of the food is chiefly, if not solely, confined to the 

 general endoderm, the epithelium of the mesenterial fila- 

 ments taking but a small share in it. By feeding certain 

 anemones with carminated albumin, or with finely chopped 

 liver of mussels, the yellowish-brown fatty globules of 

 which can be easily recognised in the substance of the 

 cells, and then examining the endoderm by a lens or by 



