KANSAS ACADEMY OF SCIENCE. 71 



First Foot. 

 ("ex., three spines. I (ex., one seta. 



Outer branch ^ ap., two setie. Inner branch < ap , two setae. 



in., three setse. I Un., three setse. 



Second Foot. 

 (ex., three spines. I fex., one seta. 



Outer branch -< ap., one spine, one seta. Inner branch -; ap., two setse. 



(.in., four setre. I (in., three setce. 



Third Foot. 

 'ex., three spines. j fex., one seta. 



Outer branch -{ ap., one spine, one seta. I Inner branch < ap., two set:e. 



four set te. (in., three setfe. 



Fourth Foot. 

 ^ ines. I Tex., one seta. 



Outer branch -i. ap.,'one spine, one seta. Inner branch < ap.,oneseta-likespine,oneseta. 



two settc. 



Fifth foot uni-articulate, trisetose. Ovisacs small, sab-oval, nearly or quite 

 meeting above the abdomen, and usually containing from five to eight eggs. 



Animal dirty blue-green; antennae lighter. Dark green pigment-masses 

 are scattered beneath the integument in various places, particularly along 

 the anterior side of the first antennae. 



Length, exclusive of setse, .68 to .78 mm. 



A very distinct species, belonging to that section of the genus which in- 

 cludes Cyclops serrulatus, Fischer, C. varicans and macrurus of Sars, and 

 C. alajensis, Uljanin. 



Cambridge. Very abundant in the dirty water of the blind ditches con- 

 nected with the artificial pond known as "Glacialis." 



Cyclops pectinifer, sp. nov. (PI. IV, figs. 1-7.) 

 Closely allied to serrulatus, from which it differs in having the posterior 

 margin of the last thoracic segment ciliated at the sides, the third apical 

 caudal seta not more than half as long as the second, and the first antennae, 

 when reflexed, covering about three and a half segments. There is also an 

 epaulette of minute cilia on the basal joint of the first antennae, a mark which 

 Claus seems to have noticed in the European serrulatus and intended to rep- 

 resent in figure 1, taf. I of "Das Genus Cyclops," though omitting it in his 

 text. The color is usually a shining yellowish brown. 

 Length, exclusive of caudal setie, 1 mm. 

 This species is common in ponds, ditches, and rain-pools about Cambridge. 



Cyclops uniangulatus, nov. sp. (PI. IV, fig. 17.) 

 Cephalothorax suboval. First four segments not angulated, nor separated 

 at the sides. Fifth produced into a strong and somewhat recurved angle at 

 either side. Anterior portion of first abdominal segment much swollen, and 

 almost angulated at the sides; not marked off from the posterior portion by 

 the conspicuous lateral indentation seen in certain other species. Last ab- 

 dominal segment posteriorly fringed with exceedingly minute spines. Cau- 

 dal stylets somewhat slender; plain, except for the usual six plumose setae. 

 Of the four terminal caudal setse, the first — considerably shorter than the 

 caudal segment — is longer than the fourth ; the second, about one and a fourth 

 times as long as the third. Pinnse of web of two intermediate terminal can- 



