336 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Color. — Body a clear yellowish gray, more or less tinged with 

 blue or green, with dark brown transverse bands across the cephalon 

 and thoracic segments; anterior antennae each with two dark bands, 

 one including the second and third, the other the tenth and eleventh 

 segments; eggs dark brown; eye very small and bright red, some- 

 times rather light in shade. 



Female. — Metasome broadly oval, breadth considerably more than 

 half the length; urosome slender, two-fifths as long as metasome; 

 caudal rami short, the outer seta close to the tip ; genital segment not 

 as long as the abdomen. Hyaline membrane on end segment of first 

 antenna perfectly smooth and projecting as a lappet at the end of the 

 segment; second and third segments of second antenna equal in 

 length, fourth segment a half longer. Basal segment of fifth leg 

 fringed on its inner margin with minute cilia ; a row of the same cilia 

 and a small seta on the surface of the segment near its base; distal 

 segment shorter and narrower, the two spines stout and denticulate, 

 the seta filiform. Ovisacs standing out nearly at right angles to the 

 body axis; posterior part of semen receptacle very short and slightly 

 emarginate at the center, but without a cleft. Total length, 1-1.8 mm. 



Male. — Larger than the female ; cephalic segment about twice the 

 length of the rest of the metasome ; fourth segment much wider than 

 the fifth and turned backward on each side of the latter ; genital seg- 

 ment with convex sides; caudal rami rather squarely truncated, the 

 longest apical setae three-fourths of the body length. First antennae 

 geniculate, the terminal portion made up of two elongate segments, 

 the end segment tapering to a pointed tip ; the middle portion, seg- 

 ments 11 to 15, inclusive, is more or less fused and moved as one piece 

 by a single broad and powerful muscle. Both segments of the fifth leg 

 are shorter and wider than in the female, but are similarly armed. 

 There is also a pair of rudimentary sixth legs at the posterior corners 

 of the genital segment, each consisting of a small lamina with three 

 setae. Total length, 1.5-2.5 mm. 



Remnarks. — This species may be distinguished by the smooth hyaline 

 membrane on the end segment of the first antenna and the lappet it 

 forms at the tip of the segment. According to Sars, this copepod is 

 found both in large lakes and small ponds and ditches, and often 

 descends to considerable depths. 



MACROCYCLOPS BISTRIATUS (Koch) 

 FlQUBE 200 



Cyclops Mstriatus Koch, Deutschlands Crustaceen, Myriapoden und Arachniden, 



pt. 21, pi. 7, 1838. 

 Pachycyclops Mstriatus Sabs, Crustacea of Norway, vol. 6, p. 67, pi. 41, 1914. 



Occurrence. — A few specimens were obtained in a small pond near 

 the outlet of John Pond, Mashpee, in the Ice Pond at Quisset, and in 

 Crockers Pond in Falmouth. 



