COPEPODS OP THE WOODS HOLE REGION 



357 



Distribution. — South Pacific, tropical Atlantic, Sulu Sea( Dana) ; 

 Japan Sea, Philippines (Brady) ; Trieste (Car) ; Canary Islands, 

 Malta (Thompson) ; French coast (Gourret) ; tropical Atlantic, 

 Mediterranean (Giesbrecht) ; Arabian Sea, Indian Ocean, Malay 

 Archipelago (Cleve) ; Red Sea, Arabian Sea (Thompson and Scott) ; 

 North Atlantic (Cleve); Adriatic (Steuer, Pesta). 



Color. — Female a grayish drab, with red pigment plentifully 

 scattered along the lateral margins, in the epimeral lappets of the 

 metasome, and across the head anteriorly and posteriorly. Corneal 

 lenses brown, with a gray spot at the center; eye red; eggs green 

 with a blue center and a gray outer shell. Male greenish blue, 

 fading posteriorly into a light 

 gray in the abdomen and caudal 

 rami; large spots of light red in 

 the posterior part of the head and 

 the first and second segments; 

 sperm ducts dark red. 



Female. — Head separated from 

 first segment; third and fourth 

 segments fused, the lappets of the 

 third segment reaching the center 

 of the genital segment ; lappets of 

 fourth segment bluntly pointed at 

 the tip ; genital segment, anal seg- 

 ment, and caudal rami in the pro- 

 portion of 24 : 9 : 10. Seta on basal 

 segment of second antenna more 

 than twice as long as the one on 

 the second segment; endopod of 

 fourth leg an elongate knob, with 

 a single apical seta. Total length, 

 1-1.15 mm. 



Male. — Body considerably more slender than in the female; head 

 separated from the first segment ; epimeral lappets of third segment 

 spreading moderately; genital segment obcordate, with a broadly 

 rounded lobe on each lateral margin near the posterior end; ab- 

 ruptly contracted behind these lobes to the width of the anal 

 segment, so that the urosome appears at first glance 3-segmented; 

 genital segment, anal segment, and caudal rami in the proportion 

 of 20 : 8 : 10. Total length, 0.8-0.9 mm. 



Remarks. — 'When alive this species may be recognized by its 

 coloration, the two sexes being strongly contrasted. It is another 

 tropical form and comes to the present area only by way of the Gulf 

 Stream. 



Figure 215. — Corycaeus obtusus: a. Fe- 

 male, dorsal (after Giesbrecht) ; b, male, 

 dorsal 



