COPEPODA 



347 



C. albidus Jurine (C. signatus Herrick) (Fig. 546). Body 1.4 mm. 

 long, and banded with blue or green; first antennae 17-jointed; fifth feet 

 2-jointed, the first joint being longer than broad, the second joint with 3 

 terminal bristles : common throughout the country in clear lakes ; Europe. 



Fig. 545 Cyclops bicuspidatus (Sussw. F. Deut.). A, furca and furcal bristles; 

 B, fifth foot; C, receptaculum seminis. Fig. 546 Cyclops albidus (Sussw. F. Deut.). 

 A, fifth foot ; B, furca and furcal bristles ; C, receptaculum seminis. 



C. serrulatus Fischer (Fig. 547). Body 1.4 mm. long, rather opaque; 

 first antennae 12-jointed; fifth feet 1-jointed and plate-like, with 3 

 terminal bristles: very common everywhere; Europe. 



C. phaleratus Koch (Fig. 548). Body 1.2 mm. long, brown in color 

 with blue feet; antennae 10 or 11-jointed and very short, not reaching 

 beyond the middle of the head: not common, but generally distributed 

 in shallow lakes and stagnant pools; Europe. 



Fig. 547 Cyclops serrulatus (Sussw. F. Deut.). A, fifth foot ; B, furca of male ; 

 C, receptaculum seminis. Fig. 548 Cyclops phaleratus (Siissw. F. Deut.). A, fifth 

 foot ; B, receptaculum seminis ; C, furca and furcal bristles. 



2. OITHONA Baird. Head terminating with a beak-like process; 

 abdomen with 4 or 5 segments; first antennae in part indistinctly jointed 

 and with very long bristles; second antennae 2-jointed: marine. 



0. similis Claus. Beak bent down at right angles to head; caudal 

 setae not plumose; body .75 mm. long and usually colorless: Woods 

 Hole; Narragansett Bay; Europe. 



FAMILY 5. HAKPACTICTDAE. 



Minute, elongate copepods with a cylindrical body, the thoracic seg- 

 ments not being much larger than the abdominal; first antennae short, 4 



