COPEPODS OF THE WOODS HOLE EEGION 327 



Male. — Body much more slender than that of the female; meta- 

 some an elongated oval, the greatest width (near the anterior end) 

 to the length as 6 : 15. Cephalic segment evenly rounded in front 

 and a little longer than the rest of the metasome; fifth segment 

 produced laterally as in the female. Urosome less than half the 

 length of the metasome; genital segment but little swollen. The 

 four abdominal segments are about the same width but diminish 

 slightly in length backward. Caudal rami longer than the last 

 two segments combined, five times as long as wide, the outer seta 

 near the center. 



First antennae twice hinged, at the fifth and tenth segments, the 

 terminal portion composed of two elongated segments, the sixth and 

 seventh segments abruptly swollen to nearly twice the diameter of 

 the adjacent segments,* very similar to some of the genera in the 

 Calanoicla. Second antennae, mouth parts, and swimming legs like 

 those of the female ; basal segment of fifth leg always fused with the 

 body. A sixth pair of legs is present at the posterior corners of 

 the genital segment, projecting far enough to be partially visible 

 in dorsal view. Total length, 0.5-0.66 mm. 



Remarks. — The reddish color of the digestive tract was probably 

 due to the food eaten, a small spherical red diatom, which was very 

 abundant in the ponds where this copepod was found. Most of the 

 specimens were covered with a growth of hairy algae, often dense 

 enougli to form a long fur effectively concealing structural details. 

 This species may be recognized by the combination of 12-segmented 

 first antennae and 2-segmented rami of the swimming legs. 



MICROCYCLOPS BICOLOR (G. O. Sars) 



Figure 195 



Cyclops bicolor Sabs, Forh. Vid.-Selsk. Christiania, p. 253, 1862; Crustacea of 



Norway, vol. 6, p. 56, pi. 34, 1913. 

 Microcyclops bicolor Kiefexl, Das Tierreich, Lief. 53, p. 70, 1929. 



Occurrence. — Found in small numbers in Crockers Pond, Fal- 

 mouth, Farm Pond, Marthas Vineyard, and a weedy pond near 

 Chatham. 



Distribution. — Sweden (Lilljeborg) ; Germany (Schmeil) ; Nor- 

 way (Sars) ; Hungary (Daday) ; Poland (Lande) ; France (Rich- 

 ard) ; Wyoming, Illinois, Wisconsin, Michigan, Minnesota (E. B. 

 Forbes, Marsh, Herrick). 



Color. — Metasome transparent and colorless, urosome a golden 

 yellow or bright orange, deepest near the anterior and posterior mar- 

 gins of the segments. First antennae and mouth parts also yellow or 

 orange in whole or in part ; eye red and close to the anterior margin 

 of the head. 



