224 BRANCHIOPODA. 



disport themselves in. Two examples of these 

 marine forms are represented in the accompanying 

 figure (Fig. 171). 



The Branchiopod Entomostracans are divided into 

 two sections, 1st, those with tufted feet (Lophy- 

 ropes)* ; and 2ndly, those with laminated feet 

 (Phyllopes).f 



The Tufted-feet Entomostracans (Lophyropes), are 

 distinguishable by the number of their feet, which 

 never exceed ten ; their legs, moreover, are cylin- 

 drical, and never flattened out into leaf-like expan- 

 sions. To this division belong 



The Cyclops (Cyclop^ so called on account of their 

 having apparently but one eye4 



The Common Cyclops (CyclopsValgaris\ (Fig. 170, i), remarkable for 

 the metamorphoses it undergoes, is common in fresh water. On each 

 .side of the tail of the female is a pellucid oval sac, filled with eggs, 

 with which it is replenished eight or ten times in the course of three 

 months ; and as the female begins to lay at an early age, supposing 

 the average number of eggs to be forty each time, the multitude of 

 which a single individual may become the progenitor, during six 

 months, is enormous. The young at their birth have only four feet, 

 and their body is rounded and tail-less : in due time other limbs 

 appear, and after a few moults the tail is developed. These little 

 creatures are capable of resisting cold in a remarkable manner. 

 They have been repeatedly seen frozen up in ice, which, on melting, 

 was full of them, as active as ever. They will also endure being 

 dried, but not for many minutes. Jurine found that out of twelve 

 individuals dried for fifteen minutes, five only recovered on being 

 restored to the water ; and that of twelve kept' dry for twenty-five 

 minutes, all perished. Yet, as in seasons of drought the ponds and 

 ditches are dried, it is most probable that they will retain life buried 

 in the mud as long as any moisture remains. The eggs, however, 

 according to Strauss, do not perish, even should the parents, but 

 become hatched in the course of four or five days, when the ponds 

 are replenished. As these little creatures grow, they change their 

 shells or transparent horny investment, like other crustaceans. The 

 change of shells is very complete ; not only the general investment of 

 the body is thrown oft* but also the outer layer of the fine branchiae 

 and the minutest hairs on the antennae. The size of the adult 

 Cyclops is about the one-sixteenth of an inch. 



* \6(f>ovpos, lophouros, tail furnished ivith long hairs ; TTOUS, pous, a 

 foot. 



f <J>uAJ\oi>, phyllon, a leaf ; TTO'VS, pous, afoot. 



J KVK\(I)\I/, cyclops, literally, " round-eyed ; ' so called after the 

 fabled giants, said to have but one eye in the middle of their fore- 

 head. 



