208 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



abundance in Cuttyhunk Harbor ; Penzance Pond and the Eel Pond, 

 Woods Hole; Katama Bay, Menenisha Pond, and Nashaquitsa Pond, 

 Marthas Vineyard. 



Distribution. — British Isles (Brady) ; coast of France (Canii) ; 

 Mediterranean (Clans) ; Red Sea (A. Scott) ; Bear Island, Franz 

 Josef Land (T. Scott) ; Adriatic (Car, Graeffe, Grandori, Pesta) ; 

 coast of Greenland (Stephen,sen) ; Kerguelen Island (Brady) ; Kiel 

 Bay (Giesbrecht) ; Gulf of Genoa (Brian) ; coast of Norway 

 (Sars) ; Little Harbor, Woods Hole (Sharpe). 



Color. — Body golden yellow, with a narrow transverse band of 

 light chestnut-brown across the anterior margin of the genital seg- 

 ment; eye dark red. 



Female. — Metasome conspicuously enlarged, the cephalic segment 

 broad, depressed, and evenly rounded anteriorly ; urosorae more than 



half the length of the metasome; caudal 

 rami twice as wide as long. First an- 

 tennae 8-segmented and densely setose, 

 the terminal ])ortion 4-segmented and 

 two-thirds as long as the basal; first en- 

 dopod much longer than the exopod, the 

 terminal claws of both rami only slightly 

 curved and spinulose along their con- 

 cave margins; inner expansion of basal 

 segment of fifth legs broadly foliaceous, 

 reaching the tip of the distal segment, 

 with a row of prominent transverse 

 chitin ribs along its inner margin, and 

 Avith five apical setae, the middle one 

 elongate; distal segment with six setae, 

 the third inner one short and hairlike. 

 Ovisac single, pear-shaped, and reaching beyond the tips of the 

 caudal rami. Total length, 0.85-1.1 mm. 



M(de. — Smaller than female, the urosome relatively more slender; 

 first antennae geniculate, the terminal portion less than half the 

 length of the basal, the aesthetask on the third segment as long as the 

 entire antenna; distal segment of second endopod twice as long as 

 wide, with a very stout spine on its outer margin; inner expansion 

 of basal segment of fifth legs with three equal setae, distal segment as 

 wide as long, with five setae, one of which is slender and nonplumose. 

 Total length, 0.7-0.9 mm. 



Remarks. — This is the largest of our American species of the genus, 

 and is most easily recognized by the prominent row of chitin ribs 

 on the fifth legs. 



Figure 138. — Dactylopusia tis- 

 boides: a. Female, fifth leg; i, 

 male, first leg ; c, male, fifth 

 leg 



