88 BIRTH OF A MEDUSOID. 



projected in regular succession in one plane, forming 

 a right angle to the distichous arrangement of the 

 cells. The vesicle contains as many as ten or more 

 developing medusoid embryos, (or rather chorions, 

 each containing several embryos) included within the 

 nutrient membranous tube, which they swell out into 

 ovate sacs. The basal part of this tube, containing 

 no embryos, is recognisable, but so tensely does it en- 

 velope themedusoids in the greatest part of its length, 

 that one would be ready to conclude these were free in 

 the cavity of the vesicle. The nutrient granules are 

 seen to circulate through the base of the tube, in some 

 specimens their course being from the medullary core 

 of the stalk into the vesicle, in others vice versa. 



I was so fortunate as to see the escape of one of 

 the medusoid embryos. The terminal swelling was 

 larger than the others, and seeing what I fancied to be 

 the tentacles of the medusoid projecting from the 

 mouth of the vesicle, I watched it. (See fig. 8.) 

 These were, however, extraneous particles of matter, 

 but it so happened that presently the real tentacles 

 began to protrude, all in a loose bundle, bent and 

 irregularly contracted, just as the polype protrudes 

 fi'om the cell. It emerged rather leisurely, and when 

 at length it was free, I was surprised to see that the 

 globose sac, which I had supposed to be the escaping 

 medusoid, was scarcely diminished, that in fact it 

 contained others, two more I should think at least, 

 from a comparison of its bulk with that of the libe- 

 rated embryo, — and that, therefore, to judge from 

 analogy, each of the swollen sacs in the ovigerous tube 

 of the vesicle contains not one, but several developing 



