86 BRITISH ENTOMOSTRACA. 



tures." Straus says he lias frequently hatched the young 

 from these ova by suddenly bringing them into a warm 

 temperature. I have, by repeated experiments, ascer- 

 tained the truth of Straus's statement, and frequently 

 witnessed the young hatched from these ephippial eggs, 

 by keeping them in my room in a genial temperature. 



On the 2d of November I took several ephippia, which 

 I found floating on the surface of a saucer full of water, 

 containing numbers of D. pulex, many of which had 

 ephippia attached to them, and placed them by themselves 

 in a glass of clear water. On the 10th, two young ones 

 were born ; 16th, one more born ; 29th, two more born ; 

 21st, one more ; and 23d, two more born. 



November 29th, I took several ephippia from the same 

 saucer as the last, and isolated them in the same manner. 

 December 5th, three young ones are born ; 6th, two more ; 

 8th, two more ; 10th, two more; and on the 16th, one 

 more, were born. 



On the 19th of November I isolated a Daphnia, with 

 the ephippium attached ; 21st, it has thrown off the 

 ephippium ; December 5th, one young one is born from 

 the ephippial eggs. I have repeatedly performed the 

 same experiment, and have always found similar results. 

 The young from these ephippial eggs do not differ from 

 those born naturally, unless that they are perhaps a little 

 longer in coming to maturity. 



In a young D. pulex, born naturally on the 8th of 

 December, it moulted the first time on the 12th, or four 

 clays after birth ; on the 21st, or thirteen days after birth, 

 it moulted for the fourth time, and had eggs ; whilst in a 

 young one of the same species, born from an ephippial 

 egg on the 5th December, the first moulting took place 

 on the 13th, or not till eight days after birth; and the 

 fourth, when she had eggs, not till the 3d January, or 

 twenty-nine days after birth. Tho periods between each 

 moulting are also longer than in the others. 



It has been asserted, as I have mentioned above, by 

 Jurine, that these ephippia are the consequences of a 



