456 EVEXESTGS AT THE MICROSCOPE. 



ceived on my retiiin that a portion of the animal was 

 outside the shelh The appearance Avas that of a small 

 colourless bladder oozing out, at an imperceptible 

 aperture; and this oval vesicle quickly but gradually 

 increased, until it was half as large as the e2:sr itself. 

 A little earlier than this point, the cilia were seen on 

 the front or lower side of the excluded portion, and 

 these began to wave languidly in a hooked form. They 

 thus seemed much longer and more substantial than 

 when rotating in the perfect animal. When excluded 

 to the extent just named, some little creatures that 

 were flitting about found it, and began to assemble 

 round it. These were far too rapid in their movements 

 to allow me to identify them before, or to perceive any 

 thing else than their swift motion and oval form ; but 

 this attraction causing them to become still, allowed 

 me to perceive their singular and beautiful structure. 

 Each consists of an oval vase open at the top, the 

 margin of which is cut into a number of little points ; 

 the sides are marked by a series of ribs, which run 

 down longitudinally, and are crossed by other trans- 

 verse ones ; the rounded bottom is furnished M'itli 

 three short points ; so that the whole reminded n)e of 

 a barrel with its staves and hoops, set on a three- 

 leofsred stool. AVithin the bodv, which is colourless, 

 are seen small dark spots, which are probably the 

 stomacli-vacuoles. Thus I identified these little bar 

 rels with Coleps Jdrtus of Ehrenberg, but I found no 

 record of their carnivorous propensities. One after 

 another whirled into the field, and after a few gyra- 

 tions became stationary at the head of the half-born 

 EucJdanis, ^wQi as I have seen vultures gather one by 

 one to a carcase. Very soon there were a dozen or 



