80 EVENINGS AT THE MICROSCOPE 



mainly dependent on a rather unimportant point of ar- 

 rangement; for the cells, instead of being set side by side 

 and end to end in quincunx fashion, to an indefinite ex- 

 tent, on two surfaces of a plane, are disposed on one single 

 surface, and in longitudinal rows of two or three cells 

 abreast; thus narrow ribbon-like branches are formed, which 

 now and then divide into two, then these into two more, 

 and so on. These branches thus become fan-shaped, which, 

 by being slightly curved, become segments of funnels; and 

 the peculiar elegance of this coralline consists in the mode 

 in which these branches are set on the stem; viz., in an 

 ascending spiral curve, so that the effect is that of several 

 imperfect funnels set one within another, but which yet 

 you perceive, by turning the whole gradually round, to 

 compose a single corkscrew band of successive fans. This 

 whole structure stands upright in its natural state, like a 

 little compact shrub growing from a root; and as a good 

 many are commonly associated together, they form a sort of 

 mimic grove, fringing the sides of dark rocky sea- pools. 



The species is called the Corkscrew Coralline, or some- 

 times the Bird's-head Coralline, the latter name being as- 

 signed to it for a reason which you will presently perceive. 

 The appellation by which it is known to naturalists is 

 'Bugula avicularia. 



We drop our specimen into a very narrow cell, com- 

 posed of parallel walls of thin glass, a very minute flat- 

 tened tank, in fact, such as can be put on the stage of the 

 microscope. Here, bathed in its native sea-water, as clear 

 as crystal, we shall see it opening and expanding its nu- 

 merous polypides with the utmost activity and evident 

 enjoyment. 



You gaze ; but you know not what you see. The pres- 



