420 



!'/,'(>' i:i:/>rNGS or the vatwnal museum. 



vol. 38. 



pointed at tip, which carries two setae, the outer of which is weak, 

 and not more than half the length of the oilier. Three outer 



marginal spine-like setae and one inner 

 one. Inner expansion rather large and 

 extending about as far as the distal 

 segment and armed with five terminal 

 spine-like setae. Fifth legs of male 

 with a shorter distal segment, which is 

 also provided with an additional seta 

 inside. while the proximal segment carries 

 but three terminal spine-like seta 1 instead 

 of live. 



Occurrence. — Collected with birge net at 

 Little Harbor, Woods Hole, Massachu- 

 setts, among surface algae, July. Also 

 brackish ponds near Woods Hole. -Inly, 

 and among Fucus along the U.S. Fisheries wharf, July. Common. 



Distribution. -British Isles (Brady); coast of France (Canu); Heli- 

 goland (Clans); Charlestown Pond. Rhode Island (Williams). 



I [G. L3. I'm Ti U'lM Si \ vri.i, was. a, 



FIFTH Foot OF FEMALE (AFTER 

 6, FIFTH FOOT OF U Ml . 



Family DIOSACCIDiE. 



Genus DIOSACCUS Boeck, 1872. 



DIOSACCUS TENUICORNIS (Claus). 



Dactylopus tenuicomis Ci u s, Die Freilebenden Copepoden, L863, p. L27, pi. 16, 



figs. 17 23. 

 Diosaecus tenuicomis Brady, Copepoda of the British Islands, vol. 2, 1880, p. <is, 



pi. 59, figs. 12-16.- G. 0. Sabs, Crustacea of Norway, vol. 5, L903, p. 146, 



j. Is. 89 and 90. 



Length. — Female about 0.8 mm.; male slightly smaller. Color a 

 golden yellow in life. 



Ft hhiIi . ( lephalic segmenl more than t w ice as long as all the free 

 segments of the metasome combined. Rostrum very prominent. 

 Furca closely set, the rami slightly longer 

 than broad at base, 1 heir apical sel se nearly 

 parallel. Anterior antenna' unusually slen- 

 der. Fifth pair of legs (fig. 1-lM with the 

 distal segment oblong in form and armed 

 on its outermost n\^c with six rather 

 unequal setae, [nner expansion of proximal 

 segment considerably produced, narrow 

 linguiform in shape, and extending beyond 

 the distal segment; armed with five mar- 

 ginal setae, the middle one very thick, the 



others thick and spinous. Two ovisacs, pyriform, and s ewhat 



divergent. 



Pig. 11.— DIOSACCUS TEKTUICORNIS. 

 a, FIFTH FOOTf-r M \1 I 



■ I [ I 



