COPEPODS OF THE WOODS HOLE REGION 



315 



proximal elbow and a semicircular process on the first segment 

 beyond the distal elbow as in flumifera. End segments of the first 

 four exopods each with two outer margin spines. Total length, 0.6- 

 0.7 mm. 



ReTTiarks. — This species may be distinguished by the number and 

 arrangement of the outer spines on the swimming legs and by the 

 ovisacs in the female. Unlike the previous species, this one is littoral 

 and comes into the harbor and may even be found in tidal pools and 

 salt ponds. 



OITHONA BREVICORNIS Giesbrecht 



Figure 190, a, h 



Oithona brevicornis Giesbrecht, Atti Accad. Lincei, Rome, ser. 4, vol. 7, p. 475, 

 1891 ; Fauna und Flora des Golfes von Neapel, vol. 19, p. 538 ; pi. 34, 1892. 



Occm^^ence. — Twenty-five males and females were obtained in 

 Penzance Pond, Woods Hole, July, 1925. 



FiGUEB 190. — a, Oithona hrevicornis, female, dorsal (after 

 Rosendorn) ; 6^ 0. brevicornis, second exopod ; c, Oithonina 

 nana, female, dorsal (after Rosendorn) ; d, O. nana, second 

 exopod 



Distribution. — Hong Kong (Giesbrecht) ; tropical Atlantic 

 (Cleve) ; Adriatic (Pesta) ; Chesapeake Bay (Wilson). 



Color. — Body transparent without any pigment markings; eye 

 reddish. 



Female. — Kostrum short and turned downward so as to be invisible 

 in dorsal view; caudal rami longer than the anal segment and at 

 least three times as long as wide, the outer seta on each ramus three 

 times as long as the ramus itself. First antennae not reaching the 



