176 Embryonic Devdopincnt of CJiirononius 



begins to move about. The cliitiuous cuticle becomes 

 evident. Tlie egg-sliell is burst open, and the larva 

 becomes free. 

 Fresh- The fresli-liatclied larva is half a millimeter long, and 



hatched -,• ^^ ■ ■ ^ •in 



larva. difters in various details from the larva of later stages. 



The blood has no red tinge ; there are no ventral 

 respiratory tubules ; the head is relatively large, and as 

 yet encloses the brain ; the nervous system is proportion- 

 ally large, and each ganglion seems to extend through 

 the whole length of the enclosing segment, or nearly so ; 

 remnants of the yolk are still to be seen in the body- 

 cavity, and within the alimentary canal. After the first 

 moult, these peculiar features disappear, and the ordinary 

 larval structure is attained. 



