30 THE AMPHIOXUS. 



readily intelligible record of several of my observations. 

 From this the alterations in the duration of develop- 

 ment will be easily seen. 



As I have already said, the eggs are liberated 

 immediately after sunset, that is in the season at 

 which my observation took place, the hour being about 

 8 o ? clock. The segmentation begins about an hour 

 after the liberation of the eggs, and is finished 

 probably a little after 12 o'clock. From, an hour and 

 a half to two hours later begins the mvagination. 

 After the lapse of another hour the segmentation 

 cavity is fully removed. I now give in a table a 

 statement of the details, as I noticed them follow one 



after the other. 



8.0 o'clock, Liberation of the eggs. 



9.0 Stage with two cells. 



10.0 ,, ., four cells. 



10.15 ., eight cells. 



10.30 ; , ,, ,, sixteen cells. 



11.0 : , ., ,, thirty-two cells. 

 11.30 



11.45 



Further steps in the division. 



12.15 . 



12.30 The cells "begin to assume the character 



of an epithelium. 

 1.0 ., Blastula. 



1.45 ., Beginning of the imagination. 

 2.45 ,, Segmentation cavity entirely removed. 



