402 THE CANADIAN NATURALIST. [Vol. X. 



the bottom in about nine feet of water. I could hardly believe 

 it was a mass of polyps, but, to satisfy my curiosity, I stripped 

 and went in for it. With the greatest difficulty I brought it 

 up in my arms, but could not get it out of the water for the 

 weight, which must have been close upon 25 lbs. It resembled 

 in form ooe of those beautiful masses known as brain coral. 



On account of the colorless nature of the ectocyst and the ex- 

 tent to which the polyps protrude, this species is the most favor- 

 able to study the general arrangements of the organs, the perfect 

 transparency allowing every detail in the structure to be seen. 

 I have found it best to cut a thin vertical slice from the mass, 

 containing on the surface not more than one or two rows of 

 polyps, and examine in the zoophyte trough with a half-inch 

 glass. It is much easier in this wi\y to obtain a view of the com- 

 plete animal than in the live box. The shock of the section 

 and removal to the trough causes complete retraction of the 

 polyps, and the surface of the coenoecium looks smooth, or presents 

 only slight tuberous elevations, corresponding to the situation of 

 the orifices. On watching one of these, the sphincter closing it 

 may be seen to relax, and the ends of the tentacles protrude 

 through the orifice, feeling about from side to side as if to ascer- 

 tain whether the "coast was clear." Finding no cause for alarm, 

 the rehixation of the sphincter proceeds, the tentacles are pushed 

 out still further, resulting at last in the complete evagination 

 of the polyp. The beautiful crescentic tuft is arranged in the 

 form of a horse shoe, or the letter U inverted, the tentacles spring 

 from each side of the summit of the double outline, the mouth 

 being at base. The number of the tentacles ranges from 50-80 ; 

 they are sigmoid in outline and increase slightly in length at 

 the extremities of the arms. The inner rows incline towards 

 each other, the outer curve gracefully in the opposite direction. 

 The surface of the tentacles is covered with cilia, which are in 

 constant motion, creating a vortex, at the apex of which the 

 mouth is situated. The tentacles act independently as well as 

 in concert, and thrust and bend in any direction, pushing away 

 objectionable matters which may have got into the throat, or are 

 present in the neighbourhood. Frequently one of the large infu- 

 soria coming withing the vortex is carried down and attempting to 

 escape is prevented by the interlacement of the tentacles which 

 bending over form a cage. The sensitiveness of these ciliated 

 arms is extreme and through them the creature obtains warning 

 of approaching danger, and instantly withdraws itself. 



