134 



BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



call}^, and curved inward ; in the left leg the second basipod and the 

 first two exopod segments are each produced at the outer distal 

 corner, the process on the second exopod segment much the largest 

 and tipped with a stout spine ; end segment twice as long as the two 

 basal segments combined and acuminate, with a single spine on each 

 lateral margin. Total length, 2.95-3.3 mm. 



Remarks. — The most conspicuous character of this species is the 

 spine on the forehead, from which its name is derived. It is mani- 

 festly " an accidental visitor from warmer and more oceanic waters 

 offshore," as Bigelow has characterized it. 



HETERORHABDUS LONGICORNIS (Giesbrecht) 



Figure 91 



Heterochaeta longicornis Giesbeecht, Atti Accad. Lincei, Rome, ser. 4, vol. 5, 



sem. 1, p. 812, 1889. 

 Heterorhabdics longicornis Giesbrecht and Schmeil, Das Tierreich, Lief. 6, 



Copepoda, p. 116, 1898. 



Occurrence. — One male and three females from trawl wings, Sta- 

 tions 2093, 2195, 2236, Albatross, south of Nantucket and Marthas 



Vineyard ; two males and one female 

 in a vertical haul, Station 20107, 

 Grampus, off Georges Bank. 



Distribution. — Tropical Atlantic 

 (Giesbrecht) ; California coast (Es- 

 terly) ; North Atlantic, Faroe Chan- 

 nel (Wolfenden) ; Malay Archipel- 

 ago (A. Scott) ; Irish Sea (Pearson, 

 Farran) ; Gulf of Maine (Bigelow). 

 Color. — Body transparent and 

 colorless, except for an irregular 

 yellow spot in the center of the meta- 

 some; eye not visible (Rathbun). 



Female. — First antennae reaching 

 six to eight segments beyond the 

 caudal rami ; metasome two and 

 one-half times as long as wide, much 

 narrowed anteriorly; urosome half 

 as long as metasome; genital seg- 

 ment as long as the first two abdom- 

 inal segments combined; second in- 

 ner terminal seta of left caudal 

 ramus jointed near its base and 

 longer than the entire body ; second 

 exopod segment of fifth leg with a compound 7-pointed spine on the 

 anterior surface near the distal margin; apical exopod spine nearly 

 as long as end segment. Total length, 2,5-3 mm. 



Figure 91. — Heterothabdus longicor- 

 nis: a. Female, fifth leg ; i, .spines 

 on second segment of fifth exopod ; 

 c, male, fifth legs 



