TElfTH ANN^UAL REPOKT 



The caudal setae are naked for about a third of their length. These 

 distinctions seem constant. 



Section ivith twelve-jointed Antennce. 



CYCLOPS SERRULATUS, Fischer. 

 (Plate V, figs, i-5, Plate VII, fig. 10.) 

 Bibliography. 



Cyclops serrulatus, Fischer Bulletin de la Soc. Imp. etc. Moscou. I 



Lilljeborg, De crust ex ord. trib. 1 



Clans, Das genus Cyclops. 



Sars, Oversigt Ferskvands Copepoder. 

 Frei-lebenden Copepoden. 



Fric, Die Krusten thiere Bohmens. 



Uljanin, Reise in Turkestan. 



Brady, British Copepoda. 

 •? Cyclops minutus, Claus, loc. cit. (- young.) 

 ? Cyclops macrurus, Sars, loc. cit. 

 ? Cyclops spinulosus, Glaus, loc. cit. 



Typical Form. 



Cephalothorax oval, compact; abdomen slender and short, suddenly 

 enlarged previous to its union with the thorax; antennae slender, 

 reaching nearly, but not quite to the last thoracic segment; the last 

 three joints are attenuated and furnish the most evident character of 



the species; formula — — ^ — v^w- — ^^ ; during life the 



antennae tend to assume the form of a rude Z, the proximal four joints 

 forming the base; antennules small, reaching about to the sixth joint 

 of antennae; jaws small with large teeth; the single segment of the 

 fifth foot with three equal spines; egg sacs oval, as long as the abdo- 

 men; eggs few, dark; caudal stylets very long and slender, spined 

 along the outer margin; lateral setae small and approximated to the 

 upp?r one; outer terminal seta short, spine-like, in life set nearly at 

 right angles to the others, spined or beaded on one margin and bristled 

 on the other; the next seta is as long as the abdomen, being somewhat 

 exceeded by the following one ; inner seta insignificant; upper seta very 

 small; length less than y^o cm. 



A larger form occurs with an elongated body and abdomen and with 

 extremelv attenuated antennae and caudal stvlets, but it is not a va 



