380 EVENINGS AT THE MICROSCOPE 



latter is clearly seen to be permeated by a beautiful sys- 

 tem of anastomosing canals, connected with the hollow 

 bodies of the polypes. Within these canals may be de- 

 tected an intermittent flow of fluid, containing particles, 

 the dancing motion of which indicates the presence of 

 ciliary action, and which, having passed in one direction 

 for a short time, are arrested, and, after a slight period of 

 oscillation, commence to flow in an opposite direction." 



The polypes which are developed from this living car- 

 pet are not all of the same form. No fewer than five dis- 

 tinct sorts exist, at one and the same time, and I doubt 

 not we shall be able to find and to identify them all, on 

 this well- grown specimen. 



First, there are the alimentary polypes, which we have 

 already cursorily glanced at. Within the space enclosed 

 by the two circles of tentacles there is a mouth with soft 

 protrusile lips, which can be pushed out and folded back 

 so as to hide tentacles, column, and all. 



Scattered among these we see numerous polypes, which 

 agree in general form with these, but with some remark- 

 able abstractions and additions. They have no mouth nor 

 stomach, and the tentacles are reduced to the smallest pos- 

 sible warts or protuberances denticulating the dilated tip. 

 But the additions are still more peculiar. From the mid- 

 dle part of the column a number, from four to nine, of 

 great oval sacs project, each attached by one end, while 

 the other stretches out horizontally, thus surrounding the 

 slender column. Each of these sacs is an ovarian capsule, 

 and contains several ova of a brilliant yellow or crimson 

 hue. Thus we have the second form that of the repro- 

 ductive polypes. 



In some places single ovarian capsules stand up alone 



