334 EDITH M. PRATT. 
rejected in exactly the same way. The zooids, therefore, 
exercise considerable choice in the selection of food. 
Colonies confined ‘in unfiltered sea water for the same 
period also refused to feed on fish ova, 
An ovum of the plaice which had been swallowed by a 
zooid was kept under observation for several hours. The 
comparatively hard shell of the egg remained rounded and 
apparently intact, but the yolk rapidly became reduced in 
quantity, and, after five hours, had almost completely dis- 
appeared, the egg case being still grasped by the ventral 
mesenterial filaments. From these experiments it is evident 
that by some means large food bodies are either broken up 
into small particles, or at least partially dissolved, in the 
coelentera before ingestion by the mesenterial filaments. 
eae 
In a third feeding experiment a fairly solid homogenous 
jelly was obtained by pounding the flesh of the whiting. A 
very small portion of this gently brought in contact with a 
pinnule was immediately seized, transferred to the mouth by 
the tentacles, and slowly swallowed. Other colonies which 
had been kept without food for thirty hours in filtered sea 
water partook of the food with equal avidity. The pounded 
flesh of cod, flounder, and plaice were also substituted for 
whiting, and proved equally acceptable to the zooids. 
In order to observe the course of the food within the 
zooids, the flesh of the fish before pounding was brightly 
stained by a dilute solution of borax carmine, and afterwards 
carefully washed in running sea water. The colonies were 
found to feed with equal avidity on the coloured fish food. 
When the colonies were expanded the course of the food 
could be easily observed through the transparent body wall 
of the zooids (figs. 2 and 3 illustrate the seizing and swallow- 
ing of food, which, on entering the ccelenteron, is grasped 
and squeezed by the ventral mesenterial filaments, and 
rapidly disappears). On microscopical examination the food 
was found to be ingested in such quantity by the filaments as 
