66 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



a 



In the mature adult the body is light brown with a pinkish hue ; at 

 each joint is a narrow band of deeper color, generally one for each 

 segment, making a double band at the joint. These bands are close 

 together and are more pronounced on the sides of the body, but run 

 well up toward the midline of the dorsal surface. They are some- 

 times connected by narrower curving bands, which give the surface 

 the appearance of fine reticulation. The mouth parts are bright red, 

 not always colored continuously, but sometimes in large blotches. The 

 bases of the first antennae are colored like the body, but the rest of 



the appendages, in- 

 cluding the swimming 

 legs, are colorless. 

 Above the mouth parts 

 is a large patch of 

 bright orange-red, of 

 indefinite limits ; at 

 times it nearly covers 

 the entire anterior end 

 of the body, at others 

 it may be limited to a 

 very small spot. The 

 eggs are large and 

 very dark bluish 

 brown, almost black. 

 (Rathbun.) 



Female. — Posterior 

 corners of fifth seg- 

 ment somewhat pro- 

 duced and narrowly 



Figure 43. — Paraeuchaeta norvegica: a. Female, dorsal roUnded; UroSOme 

 (after Sars) ; b, male, fifth legs, by Rathbun ; c, uio- ^^„„ 4.1,„„ U^if 4.y.^ 

 some, lateral (after Giesbrecht) "^"^® ^^^^^ "^^^ ^'^^ 



length of the meta- 

 some; ventral protuberance on the genital segment very large and 

 thick, and notched at the center ; second inner seta on each caudal ra- 

 mus much longer than the others ; appendicular seta nearly as long as 

 the body and strongly geniculate at its base. Total length, 7.5-8.5 mm. 

 Male.— Body very slender and elongate, the corners of the fifth 

 segment not so prominent as in the female ; urosome cylindrical, the 

 anal segment almost obsolete; no geniculate setae; exopod of first 

 legs distinctly 3-segmented; fifth legs considerably longer than the 

 urosome; right exopod 2-segmented, endopod 1-segmented, longer 

 than the basal segment of the exopod; left exopod 3-segmented, 

 second segment shorter than the first, widened distally, with the 

 inner margin coarsely dentate, thumb short and sharply pointed, 



