THE MOINA. 



636 



round the pond ; thus obeying some strange instinctive command that, though inaudible 

 to human ears, is conveyed to the myriads whom it concerns, and marshals their hosts 

 with the same wonderful discipline that governs a flock of starlings. If a shadow should 

 fall upon this belt of Daphnias, they all suddenly vanish, and appear again as soon as 

 the darkness has passed away. 



The eggs of the Daphnia are placed within the space between the shell and the body, 

 and are there kept until they are hatched, and the mother permits them to escape from 

 under her shelly covering. The young are not in the least like their parent, having no 

 shell, no abdomen, and not nearly all their limbs. The reader will take notice that each 

 of the antennse is divided into two branches, and each of these branches is subdivided at 

 its extremity into three branchlets. The specimen represented is a female, and is given 

 for the purpose of showing the manner in which the eggs are lodged between the shell 

 and the body of the mother. 



Below the Water-flea, and at fig. B, is drawn another of these wonderful little beings, 

 called the MOINA, a genus of which very few species are at present known. The colour 



C. Sida crysttdhna. 

 B. Polyphemus ptdictdus. 



P, G, H. Cyclops quadricornis. 

 B. Moina branchiata. 



A WATER-PLEA. DAphnia pultx. 

 D. Chydorux sphcerims. 



of this species is olive green, its head is round and blunt, and the lower antennae are 

 peculiarly large and muscular at the base. The carapace is much smaller behind, and 

 at the end of the abdomen are eight very short spines and two long and stout claws. 

 This species is to be found in the ponds on Blackheath, in which localities the micro- 

 scopic naturalist will detect a vast number of beautiful and even rare creatures that are 

 seldom seen in other places. 



On the back of the Moina is seen a dark mass, which, on account of its shape, is 

 called the ephippium, or saddle. This remarkable appendage appears upon the back 

 of the female, particularly in summer, and is divided into two capsules, each portion 

 containing one egg. The eggs which are placed in this singular resting-place are found 

 to remain unhatched through the winter, and are probably defended by this living saddle 

 from the effects of cold, just as pistols are sheltered from the inclemency of the weather 

 in their holsters. Probably, also, the saddle may serve to protect the eggs from the effects 

 of drought, when the pools are dried up by a hot and rainless autumn. When the 

 mother moults, the saddle and its contents are thrown off together with the shell, and 

 it is not uncommon to find specimens of the young swimming about with a portion of the 



