W. J. CAIRO. 



buds, which may develop into leaves or branches. This similarity of 

 growth was one of the chief reasons which enabled botanists to claim it 

 as a plant. And as if this was not sufficient, it also developed the sucker 

 at the end of the hydra into long filaments, which spread out in various 

 ways, and by a secretion enabled it to attach itsslf to some anchorage. 

 These filaments were naturally termed the root. If you observe the 

 marine plants you will observe that the root in no case seeks a down- 

 ward course. Something hard, something to which they can attach 

 themselves, is all that they require, for the marine plants do not to a great 

 extent, if indeed to any, depend on their roots to supply nourishment. 



The stem is zig-zag, sometimes sparingly branched, jointed at each 

 of the flexures, and thickened immediately below them, so as to form a 

 series of projections or rests on alternate sides. From these projections, 

 by a connecting part of 4 to 6 rings, arise the calycles. The calycles or 

 cups are bell-shaped, smooth-edged, and transparent. These calycles or 

 cups carry the polypes or hydranths, as they are called. The hydranths 

 are solely nutritive persons. Their function is to catch, swallow, and 

 digest prey. Many times I have watched them when they were feeding. 

 Every animalcule that came within range of the tentacles was speedily 

 encircled, drawn within the calycle, and swallowed. I have chopped 

 seaweed as small as I could, and tried to drop it among the tentacles. 

 It was swiftly encircled by the tentacles and immediately rejected. 

 This I cannot account for, unless I did not mince it fine enough. I do 

 not think I contaminated the food ; for, to test it thoroughly, I once 

 soaked my hands in sea water for about half-an-hour before attempting 

 to mince the weed. It made no difference. Mr Hydranth would have 

 none of it. This, then, drives me to the conclusion that they are car- 

 nivorous. Those of you who have kept and watched actinia feeding 

 must have been struck by the eagerness displayed in engulfing a worm 

 or piece of butcher meat, and the reluctancy to eat sea weeds. With 

 the weeds, I fancy the sea anemone says, " Well, I'll take it if you have 

 nothing else to offer, but I really do prefer a worm." 



Now, let us consider the internal organisation of the hydranth. As 

 I said, it has a circlet of tentacles. Unlike actinia or hydra, the tentacles 

 are solid, and cannot be lengthened or contracted by water. In the 

 centre of th'e tentacles lies the mouth, which leads into the hypostome. 

 The food here is to a great extent deprived of the surrounding water, 

 and is then passed through a sort of gullet into the gastravascular cavity 

 or stomach. The digested parts are passed through a very narrow 



