336 EVENINGS AT THE MICROSCOPE. 



stolon, after leaving the point of its origin, increases 

 rapidly in diameter, and sends out irregular branches. 

 The tips of these branches are covered with a glutinous 

 cement, by which they attach themselves tenaciously to 

 glass, or other surface near them. Having attached them- 

 selves, they expand laterally, at the same time throwing 

 out finger-like prolongations, which, as they come in con- 

 tact with each other, coalesce, until a fleshy plate is found 

 adherent to the glass. Polypes are developed both from 

 the loose branches and the attached polypary; and the 

 latter is clearly seen to be permeated by a beautiful system 

 of anastomosing canals, connected with the hollow bodies 

 of the polypes. Within these canals may be detected 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, be- 

 gin to flow in an opposite direction." 



The polypes which are developed from this living 

 carpet are not all of the same form. ISTo fewer than five 

 distinct 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 inclosed 

 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 

 remarkable subtractions and additions. They have no 

 mouth nor stomach, and the tentacles are reduced to the 

 smallest possible warts or protuberances like small teeth 

 on the dilated tip. But the additions are still more 

 peculiar. From the middle part of the column a number, 

 from four to nine, of great oval sacs project, each attached 



