64 



BULLETIN" 15 8, UNITED STATES NATIONAL MUSEUM 



Adriatic (Pesta) ; Gulf of Guinea (T. Scott) ; Arabian Sea, Malay 

 Archipelago (Cleve) ; Gulf of Maine (Bigelow). 



Color. — General color a pale grayish blue, with blotches of dark 

 red on the sides of the head opposite the mouth, on the bases of the 

 mouth parts, and at the posterior corners of the thoracic segments. 

 In the female there is a wide band of the same red across the pos- 

 terior margin of the cephalothorax on the dorsal surface. This is 

 not continuous with the lateral spots, but its end on each side is 

 broken up into numerous branches very irregularly arranged. The 

 eggs in the external ovisac are a deeper blue than the body, and are 

 more or less spotted with white. Those in the internal oviducts are 

 also blue and show quite distinctly through the body wall. The eye 



is minute and bright 

 ruby red (Rathbun). 



Female. — A pointed 

 knob projecting for- 

 ward just above the 

 base of the rostrum; 

 genital segment asym- 

 metrical, the ventral 

 process on the right of 

 the genital opening 

 much larger than the 

 one on the left; caudal 

 setae all about the same 

 length, none of them 

 elongated ; appendicu- 

 lar setae thicker than 

 the caudal setae and 

 about twice as long as 

 the body; first anten- 

 nae reaching the second 

 abdominal segment ; basipods and rami of fourth legs smooth. Total 

 length, 2,25-4 mm. 



Male.—Qody more slender than in the female; genital segment 

 symmetrical ; no appendicular setae ; exopods of fifth legs ending in 

 long stylet-shaped processes, the one on the right exopod 2-segmented, 

 the left one 3-segmented; second segment of left exopod with a 

 coarsely toothed process at the outer distal corner and a much shorter 

 smooth one at the inner corner; end segment with two short pro- 

 cesses lipped with tufts of hair; left endopod lacking, right endo- 

 pod 1-segmented. Total length, 3-3.25 mm. 



Remarks.— This species is characterized by the pointed process on 

 the forehead, by the asymmetry of the genital segment in the fe- 

 male, and by the form of the fifth legs in the male. In the present 



Figure 42. — Euchaeta marina: a, Male, fifth legs; 

 male, urosome, lateral ; c, female, dorsal 



b, fe- 



