330 EVENINGS AT THE MICROSCOPE. 



To return to the living specimen on the leaf : you see 

 seated in the angles of the branches, here and there, 

 elegant urn-shaped cells, larger than the polype cells, each 

 with a sort of shoulder and a narrow neck. The common 

 marrow passes from the joint into the bottom of these, 

 and then extends through the centre till it reaches the 

 mouth. In some of the urns this forms merely a slender 

 column, expanding at the mouth; but in others it 

 enlarges at irregular intervals into large knobs or masses 

 of granular flesh, which are confusedly grouped together, 

 eight or ten in one capsule. This latter is the most 

 interesting condition; let us watch it. 



While doing so, let me inform you that these urns are 

 the reproductive organs ; and the fleshy masses are 

 embryos of peculiar character, which are developed out. 

 of the nutrient medulla. The largest of those now under 

 observation is, as you see, moving, and slowly working 

 its way out of its glassy prison. Two or three flexible 

 finger-like bodies are protruding from the orifice of the 

 urn, and more are joining them : we see they are tentacles, 

 protruded in a loose bundle, just as the polype emerges 

 from the cell. 



It is a somewhat slow process; but at length the fleshy 

 mass squeezes itself forth, as if pushed out by some con- 

 tractile force behind; while we see the fluids, carrying- 

 granules, run into the parts of the tentacles which are 

 already free. The embryo is liberated. 



For a few seconds it appears helpless, and falls through 

 the water in a collapsed state, so that we cannot discern 

 its proper form. It gives a spasmodic contraction or 

 two, feeble at first, then more vigorous; the tentacles 

 lengthen, the body expands, and — lo ! it is not a Polype, 

 but a Medusa ! 



And now take your eye for a moment from the micro- 

 scope, and glance at this glass jar, in which the oarweed 

 with its colony of Zoophytes has been standing for a few 



