92 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Endopod of right fifth leg short and straight ; basal exopod 

 segment scarcely one-third as long as second segment ; left 

 endopod 1-segmented, cylindrical and neither spatulate nor 



crenate sanguineus (p. 93) 



3. Endopod of right fifth leg the same length as basal segment of 

 exopod ; latter with a quadrangular hyaline appendage ; left 



exopod tipped with a chela birgei (p. 98) 



Endopod of right fifth leg definitely longer than basal exopod 

 segment ; no hyaline appendage ; left exopod tipped with a 

 single fingerlike process; no chela oregonensis (p. 99) 



DIAPTOMUS MINUTUS Lilljeborg 



• FiGUEB 62 



Diaptomus minutus Lilljeboeg, Mem. Soc. Zool. France, vol. 2, p. 50, pis. 1, 3, 

 1889.— Maksh, Trans. Wisconsin Acad. Sci., vol. 15, p. 426, pis. 17, 18, 1907. 



Occurrence. — Fresh Pond, 

 Nobska Point, Woods Hole, 

 500, both sexes; John Pond, 

 Mashpee, 500, both sexes ; Great 

 Pond, Barnstable, 100, both 

 sexes; Long Pond, Newton, 

 500, both sexes; Upper, Mid- 

 dle, and Lower Cotuit Ponds, 

 Barnstable, 200, both sexes; 

 Hinckleys Pond, Harwich, 50, 

 both sexes; Mashpee Pond, 

 Mashpee, 25, females; French 

 Watering Place, Naushon Is- 

 land, 25, females; Crescent 

 Lake, Centerville, Barnstable, 

 75, both sexes; Seymour Pond, 

 Brewster, 25, females; Long 

 Pond, Brewster, 100, both 



Figure 62. — Diaptomus minutics: a. Female, SCXeS ; Shallow Pond, Barn- 

 dorsal; b, female, fifth legs; c, male, fifth ^^^^^^^^ ^qq^ ^^^j^ g^^^g . Qyster 



Pond, Falmouth, 25, females; 

 West End Pond, Naushon Island, 15, females; Browns Pond, Fal- 

 mouth, 15 females; Jenkins Pond, Falmouth, 20, females; Mares 

 Pond, Falmouth, 50, both sexes; Lovells Pond, Barnstable, 75, both 

 sexes. 



Distribution. — Greenland (Lilljeborg) ; Iceland (De Guerne and 

 Richard) ; Newfoundland (Schacht) ; Great Lakes, Michigan, Wis- 

 consin (Marsh). 



Color. — Body fairly transparent, mouth and surrounding regions, 

 and sometimes the entire cephalothorax bright orange-red; ends 

 of first antennae, particularly in the male, reddish; thoracic seg- 

 ments outlined dorsaily in blue; ovaries and oviducts dark blue; 

 eggs pale bluish green, with a reddish center and nearly opaque; 

 eye dark blue. 



