COPEPODS OF THE WOODS HOLE EEGIOlSr 29 



ment of basipod of first legs with a strong hook on its anterior sur- 

 face; first basipod segment of fifth legs with setae on its inner 

 margin. Total length, 3-3.25 mm. 



Male. — Head separated from first segment of thorax ; first antennae 

 straight; mouth parts strongly retrograde. End segments of the 

 second, third, and fourth exopods with their outer margins toothed ; 

 fifth legs like the fourth, but the basipods and the first and second 

 segments of the left exopod are considerably lengthened, while the 

 end segment is shortened. Total length, 2.5-2.85 mm. 



Remarks. — This is evidently a tropical species, but comes north in 

 the Gulf Stream and is likely to be found anywhere within the 

 present area. It is a small species and can be recognized by the 

 curved hook on the anterior surface of the first basipods, which is a 

 constant character. Its small size and limited numbers make it of 

 little economic value. 



Genus UNDINULA A. Scott, 1909 



Head fused with the first segment ; fourth and fifth segments sepa- 

 rated; urosome symmetrical and 4-segmented. Rami of the first 

 four pairs of legs 3-segmented; the second segment of the second 

 exopod in both sexes deeply notched in the species here included. 

 Fifth legs of female like the other pairs, rami 3-segmented ; right leg 

 of male much reduced in size, biramose, the rami 3-segmented, the 

 endopod considerably smaller than the exopod; left leg uniramose, 

 or with a rudimentary 1-segmented endopod; exopod greatly en- 

 larged, its end segment converted into a powerful 2-parted prehensile 

 organ. One species, 



UNDINULA VULGARIS (Dana) 

 FiGUEE 14 



Undina vulgaris Dana, Proc. Amer. Acad. Arts and Sci., vol. 2, p. 22, 1849. 

 Undinula vulgaris A. Scott, Siboga-Bxiieditie, 29a,, Copepoda, pt. 1, p. 16, 1909. 



Occurrence. — Twenty-five males and females from trawl wings at 

 Stations 2204, 2210, 2219, Albatross; 10 males and females from sur- 

 face tow on Georges Bank, September 15, 1874. 



Disti'ibution. — Tropical Atlantic, Samoa Islands, Sulu Sea, Banca 

 Straits (Dana) ; Australia, New Guinea, Philippines, Hawaiian 

 Islands, Fiji Islands, tropical Atlantic (Brady) ; Hong Kong, Atlan- 

 tic and Pacific Oceans (Giesbrecht) ; tropical Atlantic (Cleve) ; Red 

 Sea, Indian Ocean (Thompson and Scott) ; Arabian Sea, Malay 

 Archipelago (Cleve). 



Color. — Entire body a uniform brick red, which persists even after 

 40 years' preservation in strong alcohol. 



Female. — Head fused with the first segment; fifth segment with 

 pointed posterior corners turned ventrally; caudal setae symmet- 

 71937—32 4 



