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BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



along the shores of Katama Bay, Marthas Vineyard, July, 1926; 

 always among algae. 

 Distribution. — Coast of Norway (Sars). 



Color. — Body transparent, of a faint yellowish-gray tinge, the 

 contents of the digestive tract a bright red ; eggs grayish white ; eye 

 brick red. 



Female. — Urosome three-fifths as long as metasome, its segments 

 densely fringed with spinules along the posterior margins on the 

 ventral and lateral surfaces; caudal rami wider than long, the 

 inner apical setae thickened at their bases. 



First antennae 8-segmented, the four terminal segments com- 

 bined twice as long as the fourth segment; exopod of first legs 



longer than basal endo- 

 pod segment; distal seg- 

 ment of third exopod 

 with four spines and 

 four setae, one of the lat- 

 ter almost obsolete; dis- 

 tal segment of fifth legs 

 oval, with six setae, the 

 two apical ones filiform, 

 basal expansion reaching 

 beyond center of distal 

 segment, obliquely trun- 

 cated, with five stout 

 plumose setae, the sec- 

 ond and third outer ones 

 subequal and much 

 longer than the others. 

 Total length, 0.6-0.75 

 mm. 

 Male. — Second basipod of first legs with two curved blunt processes 

 and an acuminate spine on the inner margin ; distal segment of second 

 endopod swollen through the middle, with a single long apical seta 

 and two outer spines, the proximal one much the larger and blunt at 

 its tip ; fifth legs much reduced in size, basal expansion conical, tipped 

 with two equal setae, distal segment short and narrow, with six setae, 

 the apical one filiform. Total length, 0.5-0.65 mm. 



Remarks. — This copepod lives crawling about through the meshes 

 of the blanket algae that cover the ponds on Chappaquiddick Island. 

 It feeds largely on red diatoms, a fact that accounts for the color of 

 its digestive tract. Some of the algae was brought home and placed 

 in a shallow aquarium, and the copepods remained alive for 18 days, 

 long before which the algae had developed enough stench to render 

 it decidedly obnoxious. 



Figure 147. — Atnphimcus palUdus: a, Male, second 

 leg ; b, female, flfth leg ; c, male, fifth leg 



