88 BRITISH ENTOMOSTRACA. 



instituted a series of experiments upon this subject, with 

 regard to the Daphniae, and his results are, that after 

 having exposed the insect with eggs in the matrix for a 

 considerable time to a dry atmosphere, and then replacing 

 it in water, the eggs did not lose their vitality, but were 

 after a time hatched as usual. Sulzer, as quoted by 

 Straus, says the parents return to life also ; but in the 

 experiments reported by Straus, he never found either the 

 mother or the eggs recover their vitality. The food of 

 these animals, according to Straus, consists of vegetable 

 matter, and not animal ; but I have no doubt that they 

 are carnivorous, as I have invariably found, that of two 

 groups placed in separate vessels of clear water, the one 

 having only particles of vegetable matter placed beside 

 them, while with the other there were also introduced in- 

 fusorial animalcules, the latter were much stronger and 

 more active, and throve better than the former. (Vide 

 supra, p. 6.) 



I have divided the animals belonging to the family 

 Daphniadae into two sub-families, according to the number 

 of their feet and the construction of their large antennae 

 or rami. 



DAPHN1NA. 



Five pairs of feet. Inferior antennae, two-branched ; 

 one branch divided into four, the other into three articu- 

 lations. 



1. DAPHNIA. Head produced downwards into a more 

 or less prominent beak. Superior antennae exceedingly 

 small, one-jointed, and situated under the beak. 



2. MOINA. Head rounded and obtuse. Superior 

 antenna; of considerable length, one-jointed, arising from 

 the front of the head, near the centre. 



3. MACROTHRIX. Head terminating anteriorly in a 

 sharp beak, directed straight forwards. Superior an- 

 tennae of considerable size, one-jointed, and hanging 

 pendulous from the beak. 





