COPEPODS OF THE WOODS HOLE REGION 



31 



KEY TO THE SPECIES 

 FEMALES 



1. Urosome made up of 4 segments elongatus (p. 31) 



Urosome made up of 3 segments 2 



2. Head indented on either side of the frontal margin ; genital seg- 



ment distinctly longer tlian wide attenuatus (p. 32) 



Head ^Yithout indentations on the frontal margin ; genital segment 

 distinctly wider than long monachus (p. 33) 



MALES 



1. Both fifth legs present 2 



Right fifth leg entirely lacking monaclius (p. 33) 



2. Exopod of second antenna just reaching distal margin of first 



segment of endopod; left fifth leg shorter than fourth 



leg attenuatus (p. 32) 



Exopod of second antenna scarcely reaching middle of first 

 segment of endopod ; left fifth leg as long as fourth leg_ elongatus (p. 31) 



EUCALANUS ELONGATUS (Dana) 



FlGXXEE 15 



Calanus elongatus Dana, Proc. Amer. Acad. Arts and Sci., vol. 2, p. 18, 1849. 

 Eucalanus elongatus Giesbbeoht and Schmeil, Das Tierreich, Lief. 6, Copepoda, 

 p. 20, 1898. 



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

 at Stations 2093, 2173, 2195, 2219, 2236, 2230, Albatross, southwest 

 of Marthas Vineyard. 



Distnhution. — S ii 1 u Sea (Dana) ; 

 Nizza (Claus) ; East Indies (Streets) ; 

 Mediterranean, Pacific coast of South 

 America (Giesbrecht) ; California coast 

 (Esterly) ; North Atlantic (Cleve) ; In- 

 dian Ocean (Thompson) ; Iceland, Fargo 

 Channel (With) ; Gulf of Maine (Bige- 

 low). 



Color. — Usually colorless and very 

 transparent; eye small and bright red. 

 There is sometimes a varying degree of 

 red in the body, now limited to a single 

 oil drop near the posterior end of the 

 thorax, again confined to a small spot at 

 the base of the mouth parts, occasionally 

 in scattered blotches. 



Female. — Head regularly triangular; 

 fifth segment with spines at the posterior 

 corners; genital segment longer than 

 wide ; urosome 4-segmented ; second inner seta of right caudal ramus 

 elongated. Proximal segment of the endopod of the second antennae 

 more than three times as long as wide, and one-fifth longer than the 

 distal segment. Total length, 5.75-8.5 mm. 



Figure 15. — Eucalanus elongatus: 

 Oj Female, dorsal ; 6, fifth legs 

 of male 



