14 



COLD SPRlNi; HARBOR MONOGRAPHS. 



VII. 



Cyclops Parens, Herrick (Plate VI.). 



C. parens, Hkrrick (Plate VI., Figs, i and 2), is especially 

 abundant in the collections made in the early spring on Long 

 Island, and the adult is often accompanied by the later transitional 

 stages of the young. 



The form closely resembles C. Ajiicrieaiiiis, Marsh. As in the 

 case of the latter species, the thoracic segments appear when slightly 

 pressed to be loosely articulated. 



The antennae contain seventeen segments and reach about to the 

 posterior margin of the cephalo-thorax. The armature of the seg- 

 ments is very constant, the typical number of hairs being as follows : 

 8, 4, 2, 6, 4, 2, 2, I, I, o, I, 2, o, I, 2, 3, 7. 



The caudal stylets are relatively long and slender, and bear two 

 long setae, the median seta exceeding the outer one in length. The 

 remaining hairs are short and inconspicuous. They may become 

 slightly setose or remain unchanged. 



The armature of the swimming feet of the adults is as follows: 



Foot No 



Ramus, Outer or Inner. 



Outer Spines 



Apical Spines 



Apical SetK 



Inner Setae 



II 



III 



1 

 1 

 3 



11 

 1 

 1 

 3 



IV 



^seta. ^weak. 



The rudimentary fifth foot of C. parens has a basal segment 

 wider than long and bears a single seta. The distal segment is 

 longer than wide and carries a single seta and a short spine of 

 variable size (Plate VI., Figs. 4, 7). The receptaculum seminis 

 of parens resembles that of C. brezHspiiiosus (Plate VI., Fig. 8, and 

 Plate VII., Fig. 4). 



During development the number of segments in the rami of the 

 swimming feet increases in correlation with that of the antennae. 

 For when the antennae have nine or ten joints, the rami have two 

 segments, but when the antennae acquire eleven joints the rami 



