CYCLOPS. Ill 



mountain form, which I at one time thought distinct, 

 and which differs from the typical serrulatus chiefly 

 in its darker colour and in the less profuse ciliation 

 of the various setae, is figured in PI. XXII, figs. 

 714. 



8. CYCLOPS MACRURUS, Sars. PI. XXIV, figs. 1 5. 



Cyclops macruriis, Sars. Oversigt Ferskvandscopepoder, p. 45 



(1863). 



Cephalothorax elongato-ovate ; last segment fringed 

 at the angles with numerous fine hairs (fig. 3). 

 Anterior antennae (fig. 2) very short and slender, 

 12-jointed, about equal in length to the first 

 segment of the cephalothorax, closely resembling 

 those of G. serrulatus except in length. The five 

 pairs of feet differ not at all from those of G. 

 serrulatus. Abdomen much attenuated ; penultimate 

 segment bordered on the posterior margin (fig. 4) 

 with a series of spine-like setae; the other segments 

 finely pectinated. Caudal rami exceedingly long and 

 slender, equalling in length the three preceding 

 segments ; smooth for the greater part of their 

 length, but towards the extremity of the external 

 margin bearing a series of four or five small spines 

 (fig. 5). The innermost of the two principal caudal 

 setae is about half as long again as the outer, and 

 both are finely plumose. Ovisacs adpressed. Length 



nearly -^th of an inch (1*3 mm.). 



This species is distinguished from the foregoing by 



the short antennae, the very long and slender tail 



