22-i BKAXCHIOPODA. 



disport themselves iu. 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 2ndlv, those with laminated feet 

 (Phyllopes).t 



The Tufted-feet Entomostracans {Lophi/ropes), 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 (Ci/dops), so called on account of their 

 liaving apparently but one eye.^ 



The Common Cyclops (Cychj^sVulgaris), (Fig. 170, i;, remarkable for 

 the metamorphoses it midergoes, is common in fresh water. Un 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 coui-se of three 

 mouths ; and as the female l^egins to lay at an early age, supposing 

 the average number of eggs to he forty each time, "the multitude of 

 whicb a single individual may l^ecome the progenit^->r. dming six 

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

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

 appear, and aft<,-r a few moults the tail is developed. Tliese 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 endme 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 drv* 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 bm-ied 

 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 fom- or five days, when the jx)nds 

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

 shells or transj^arent horny investment, like other crustaceans. The 

 (^liange of shells is very complete ; not only the general investment of 

 the lx)(ly is thrown oft', but also the outer layer of the fine branchina 

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

 Cyclops is about the one-sixteenth of an inch. 



* \6(povpos, lophouros, tail furnislied with long hairs ; irovs, pons, a 

 foot. 



t <pv\7.ov, phyllon, a haf ; tto'us, pons, a foot. 



X KUK\cx>\l/, Cyclops, literally, " round-eyed ;' so called after the 

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

 head. 



