COPEPODS OF THE WOODS HOLE REGION 



385 



the metasome, 5-segmented in the female; genital segment enlarged 

 but little; abdomen tapered considerably; caudal rami short, nar- 

 row, divergent. First antennae 6-segmented; second antennae 3- 

 segmented, with large terminal claws; maxillipeds in normal posi- 

 tion behind the other mouth parts. Kami of first legs 1-segmented, 

 of the three following pairs 3-segmented; fifth legs uniramose, 1- 

 segmented. A single species. 



ANCHISTROTOS OCCIDENTALIS Wilson 



Figure 237 



Anchistrotos occidentalis Wilson, Proc. U. S. Nat. Mus., vol. 64, art. 17, p. 6, 

 pi. 2, figs. 10-18, 1924. 



Occurrence. — Taken from the gills of the orange file fish {Alutera 

 schoepfii) at Woods Hole. 



Distribution. — Not found outside the present area. 



Color. — B o d y a uniform yellowish 

 white, becoming tinged with brown in 

 preservatives; eye invisible; eggs white. 



Female. — Cephalic segment strongly 

 arched dorsally and reentrant ventrally; 

 fifth segment widened through the bases 

 of the fifth legs and considerably wider 

 than the genital segment. Of the four 

 abdominal segments the basal one is the 

 longest and the third one is the shortest; 

 the caudal rami are widely separated 

 and divergent, each with two unequal 

 apical setae. The corrugated area forms 

 a fingerlike process on the outer margin 

 of the end segment of the second an- 

 tenna; the terminal claw of the max- 

 illipeds is long, slender, and sickle- 

 shaped; the fifth legs are spatulate, with four apical setae. Total 

 length, 1.75 mm. 



Male. — Unknown. 



Remarks. — This parasite, like its host, is evidently a straggler from 

 farther south, and will only be found in very limited numbers. 



Suborder NOTODELPHYOIDA 



Fifth thoracic segment forming in the male a movable articulation 

 with the fourth, but firmly attached to the sixth. In the female 

 there is usually no movable articulation, the segments of both 

 metasome and urosome in this region being rigidly fused and sup- 

 porting on their dorsal surface an incubatory pouch. The excep- 

 tional females that bear normal ovisacs are articulated like the 



Figure 237. — Anchistrotos oc- 

 cidentalis: a. Female, dor- 

 sal ; b, female, fifth leg 



