COPEPODS OF THE WOODS HOLE KEGION 

 AETIDEUS ARMATUS (Boeck) 



Figure 26 



45 



Pseudocalanus armatus Boeck, Forh. Vid.-Selsk. Christiania, 1872, p. 38. 

 Aetideus armatus Sars, Crustacea of Norway, vol. 4, p. 25, pis. 13, 14, 1901. 



Occurrence. — A single female in the trawl wings, Station 1039, 

 Fish Hawk; 2 females in the trawl wings, Station 2195, Albatross^ 

 south of Nantucket. 



Distribution. — Torres Strait (Brady) ; Gibraltar, tropical Pacific 

 (Giesbrecht) ; Malta (Thompson) ; Mediterranean (Giesbrecht) ; 

 North Sea, North Atlantic (Farran) ; Indian Ocean (Thompson and 

 Scott) ; Adriatic (Steuer, Pesta) ; California coast (Esterly) ; Malay 

 Archipelago (A. Scott) ; Gulf of Guinea (T. Scott) ; Gulf of Maine 

 (Bigelow). 



Color. — All the appendages and the caudal 

 rami are transparent and colorless; the body 

 is about half transparent and the other half 

 orange or blood red. Through the long cepha- 

 lothorax the band of red is quite intense; the 

 posterior segments are all red, but the color is 

 weak except at the joints, where it is intense 

 and deep. There is a small red dot on each 

 side where the first antenna joins the head 

 (Rathbun). 



Female. — Metasome elongate-elliptical, width 

 a little more than a third of the length ; caudal 

 rami about three times as long as wide, con- 

 siderably longer than the anal segment, finely 

 ciliated on their inner margins; a long non- 

 plumose seta on the dorsal surface of each 

 ramus near the distal end. Total length, 

 1.8 mm. 



Male. — Smaller and more slender than the 

 female, the head considerably narrowed an- 

 teriorly and devoid of a rostrum. Spines at 



posterior corners of fifth segment smaller and shorter than in the 

 female. Left fifth leg nearly as long as the urosome, the third seg- 

 ment the longest, the end segment slender and fringed with fine cilia. 

 Total length, 1.25-1.45 mm. 



Remarks. — The female can be recognized by the highly vaulted 

 forehead and the coarse spines at the posterior corners of the fifth 

 segment; the most distinctive character of the male is the single left 

 fifth leg, with its five segments. 

 71937—32 5 



a 



FiGDRB 26. — Aetideus ar- 

 matus: a. Female, dor- 

 sal ; h, fifth leg, male. 

 (After Sars) 



