THE ROMANCE OF NATURAL HISTORY. 



that is in the egg-producing condition ; a selection 

 which the perfect transparency of the tissues en- 

 ables us to make readily. The ovary occupies the 

 ventral region, and when an egg is in process of 

 development, its mass gradually becomes more 

 and more opaque, and larger and larger, until 

 nearly half of the bulk of the body is filled up 

 with it. Then suddenly it is discharged, a soft 

 and shell-less mass, but immediately on exclusion 

 it takes its regular oval figure, and the integu- 

 ment presently hardens into a shell. 



Patience, moreover, for a few hours will be re- 

 warded by a sight of a living well-formed animal 

 hatched from this new-laid egg. At first it re- 

 mains so turbid as to be almost opaque; but in 

 the course of a couple of hours or so, it is per- 

 ceptible that the contents are becoming pellucid 

 flesh, and developing into organs and viscera, the 

 integuments and membranes becoming more and 

 more manifest in their overlying infoldings. An- 

 other hour passes; and now the action of the 

 frontal cilia is discernible; at first as faint fitful 

 waves, which, however, become momentarily 

 more vigorous, until at length their lashings are 

 distinct and incessant. Meanwhile the eye hag 

 been coming into view, visible first as a pale rec 

 tinge in a particular spot near the middle of th( 

 egg, and gradually acquiring a definite outline, 

 and a ruby-like translucent brilliancy. After this 

 a little working action is perceived behind the eye, 

 which shews that there the jaws are already de- 

 veloped, and that their proper muscles are assu- 

 ming form and contractile power. About four 

 hours have now elapsed since the egg was laid; 

 the movements of the embryo are now vigorous, 

 sudden, and spasmodic, the folds of the body- 

 integument change their places, and the cilia work 

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