574 



ZOOLOGY 



SECT, 



Cyclops (Fig. 451, 1) has been compared in form to a split pear, 

 the broad end being anterior, and the convex surface dorsal. 

 The first thoracic segment is fused with the head, and the 



anlf 



2.Ca I o c a lanus 



FIG. 451. Free-swimming Eucopepoda. la, female Cyclops, from the right side ; b, dorsal 

 view ; C, antenna of male ; D, swimming-foot, alxl.l, first abdominal segment ; ant.l, 

 antennule; ant.2, antenna; c. th. cephalothorax ; e. median eye ; en. endopodite ; e.s. egg- 

 sac ; ex. exopodite ; OP. ovary ; pr.l, pr.2, protopodite ; ?. rostrum ; t.f. swimming-feet ; 

 th.g, th.6, thoracic segments. (After Huxley, Gerstaecker, Hartog, and Giesbrecht.) 



cephalothorax (c. tli.) thus formed is covered with a carapace pro- 

 duced in front into a short spine or rostrum (r), near the base 

 of which, on the dorsal surface, is the median eye (e). There are 

 five free thoracic segments: the last (th. 6} bears the genital 



