132 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



HETERORHABDUS NORVEGICUS (Boeck) 



Figure 89 



HeterocJiaeta norvegica Boeck, Forh. Vid.-Selsk. Christiania, 1872, p. 40. 

 Ucterorhabdus norvegicus Saes, Crustacea of Norway, vol. 4, p. 118, pis. SO, 81, 1902. 



Occurrence. — Five males and females in a vertical haul, Station 

 10295, Grampus, off Georges Bank; six males and females, vertical 

 haul, Station 20044, Grainpus. 



Distribution. — Norwegian coast (Boeck, Sars) ; 

 (Sars) ; Greenland, Faroe Channel (Norman) ; 



(Mrazek, Damas 



Polar Basin 



Arctic Ocean 



and Koefoed, 



Gulf of Maine 



Vanhoffen) ; 

 (Bigelow). 



Color. — Body highly transpar- 

 ent and colorless, with a faint 

 tinge of yellow ; the metasome 

 contains scattered oil globules, 

 which are highly refractive; the 

 muscles become pink in formalin. 

 Female. — M e t a s o m e nearly 

 three times as long as wide, nar- 

 rowed anteriorly; frontal projec- 

 tion knoblike ; head with a dorsal 

 cervical depression ; urosome, 

 including caudal rami, half as 

 long as metasome ; genital segment 

 swollen anteriorly and ventrally ; 

 left caudal ramus larger than 

 right, second inner seta twice the 

 length of the metasome: exopod 

 of fifth legs twice as long as the 

 endopod, falciform spine on in- 

 ner margin of its second segment turned squarely inward and as long 

 as end segment, apical spine half as long. Total length, 3.8-4.2 mm. 

 Male. — Body more slender than in the female, urosome longer and 

 narrower ; left first antenna geniculate, not much swollen, its terminal 

 portion 4-segmented ; the inner sausage-shaped process on the second 

 basipod of the right fifth leg is abruptly curved and fringed with 

 coarse hairs ; the first exopod segment is produced at the outer corner, 

 the second segment is oval in form, with an irregular protuberance on 

 the inside ; the left exopod is about the same length as the right, the 

 end segment is lamellar and is tipped with a short outer spine and a 

 slender flexuous inner one. Total length, 3.75—4.2 mm. 



Rerfiarhs. — This species may be recognized by its large size, by the 

 relative shortness of the first antennae, and by the fifth legs, espe- 



FiGUEB 89.- — Heterorhaidus norvegicus: a, 

 Female, dorsal (after Sars) ; 6, female, 

 fifth leg ; c, male, fifth legs 



