no. 1653. PACIFIC OOAST GOPEPODS WILSON. 4HH 



ARGULUS NIGER Wilson. 

 Argultis niger Wilson, L902, p. Til. pi. .win. 



Host and record of specimens. -The two specimens on which this 

 species was founded were obtained by the steamer Albatross in Oc 

 tol»er. L899, from the Pacific coasl Dear Portland, Oregon. The name 

 of the host was not given. 



Family KR( S ASI LI DM. 



Genus ARTACOLAX, new. 



First thorax segment united with the head i<> form the carapace, 

 which is much wider than it is lon<r. Second thorax -cement free 

 and as with' as tin- carapace or nearly so. Third and fourth seg 

 ments fused and the same width as the second segment or hut little 

 narrower. Fifth segment free and abruptly narrowed to a half or 

 even a third of the width of the preceding fused segments. Genital 

 segment enlarged hut little: abdomen narrow and linear. 



First antenna' very Large; basal joint often armed with large 

 spinous processes. Second antenna' t wo- jointed. Mouth organs 

 close to the antenna-: second maxillipeds large and attached outside 

 the other organs as in Bomolochus; furnished, as in that genus, with 

 S-shaped terminal claws, but without any plumose setae. First 

 swimming Legs with very wide rami, armed with Large flattened 

 plumose seta-: exopod one-jointed, endopod three- jointed. 



Male like the female, but with the second maxillipeds in norma] 

 position behind the other mouth part- and armed with the usual 

 terminal curved claw. 



Type-spt cies.— . 1 rtacolax ( Bomolochus > ardi ola Kroyer. 



(. I /■/</< ,,/,/,,•. 'opracD, to hang on, and *oAa£. a parasite). 



This genus is distinguished from Bomolochus by the great com 



parative width of the first four thorax segments, by the fusi< f the 



third and fourth segments, so that there are apparently but three 

 fiye segments in front of the genital segment instead of four, a- in 



Bomolochus, by the lack of plumose seta' on the second ma \ il 1 iped-. 



by the increased width of the rami of the first swimming Legs, and 

 the fact that the exopod has 1ml a single joint. 



This new genus will include the following species in addition to 

 the type: Bomolochus chatoessi Kroyer; 11. cornutus Clan-: B. scom- 

 beresocis Kroyer: and probably B. hirsutus Hesse, although the last 

 mentioned species is so poorly described thai ii is impossible to Locate 

 it exactly. 



l'PM-. X. M. \nl. .\ X X \ -OS 28 



