74 



after fertilization, I could only find a very few embryos 

 after a long, patient and careful search, which occupied 

 several hours. Those discovered were similar in all re- 

 s^Dects to those last described, and as figured by Brooks, 

 in No. 44. 



On the lf)th, I met with a total failure in my search for 

 the embryos, and it was both long and carefully con- 

 ducted, and the same want of success attended me on the 

 16th, when I gave up the attempt to further trace the 

 development. 



It will be observed that I could not find any embryos 

 of a more advanced stage than those figured by Brooks, 

 and that owing, probably, to the irregular rate of seg- 

 mentation, I found them at the latter stages at iDeriods 

 varying from three to eight days. 



It is not probable that the disappearance of the embryo 

 was due to a deficient supply of water, for during the 

 latter days of their existence they were far more liberally 

 supx^lied than before. Neither is it x^robably due to 

 change of temperature, for, as will be seen by the follow- 

 ing tables of maximum and minimum temperatures, the 

 range of temperature was about the same throughout the 

 eight days : 



Date, 



Max. Temp. 



Min. Temp. 



Biff. 



6 





71^ 



70^ 



V 



7 





71^ 



64^ 



70 



8 





73^ 



64^ 



9^ 



9 





790 



60^ 



9^ 



10 





75^ 



62^ 



13^^ 



11 





740 



60^ 



140 



12 





71^ 



61^ 



10^ 



13 





77Q 



64^ 



13^ 



14 





75^ 



m"" 



9^ 



15 





72^ 



64^ 



8^ 



The water supplied to the embryos was always allowed 

 to stand a sufficient time to acquire the temperature of 

 the air before being added to that already in the jar. 



