COPEPODS OP THE WOODS HOLE EEGION 



203 



HALITHALESTRIS CRONI (Kr0y«r) 



Figure 134 



Ilarpaoticus croni Kr0yer, Gaimard's voyage en Scandinavie, Atlas, pi. 43, fig. 



3, a^n, 1845. 

 Ilalithalestris croni Sabs, Crustacea of Norway, vol. 5, p. 118, pi. 72, 1905. 



Occurrence. — Taken in surface tows at Stations 528 and 627, 

 Grampus^ July, 1894, the last station close to the tip of Cape Cod. 



Distrihution. — British Isles (Brady) ; coast of Spitzbergen (T. 

 Scott) ; coast of Norway and Finmark (Sars) ; Greenland (Stephen- 

 sen) ; Cape Cod (Sharpe). 



Color. — Body semitransparent, of a light green color, deepened 

 along the margins of the segments, and nearly always filled with clear 

 oil bubbles of varying sizes. 



Female. — Body possessing a peculiarly smooth appearance ; genital 

 segment fully as wide as the metasome, as long as wide, with lateral 

 traces of a median division; caudal rami 

 at least four times as long as wide, the 

 longest apical seta about half the body 

 length; urosome segments fringed along 

 their posterior margins on the ventral sur- 

 face with small spinules; ovisac large and 

 single, reaching the middle of the caudal 

 rami. First antenna not reaching the pos- 

 terior margin of the cephalic segment ; inner 

 expansion of basal segment of fifth legs 

 well developed and armed with five setae, 

 the middle one the longest; distal seg- 

 ment oval, with six setae, the two apical 

 ones short and very slender, the one next to 

 them on either side considerably elongated. 

 Total length, 2.2-2.45 mm. 



Male. — Smaller than the female; first antennae geniculate, the 

 segments of the terminal portion more or less fused and clawlike. 

 Exopod of first legs very slender and tipped with two unequal 

 spines and a seta, all ciliated. Inner expansion of basal segment 

 of fifth legs very short, broadly triangular, and armed with three 

 setae; distal segment subovate, the inner margin ciliated, the outer 

 margin sparsely setose, with three apical setae. Total length, 

 1.7-2 mm. (Called Thalestris serrulata by Brady.) 



Remarks. — This is one of the largest harpactids and is pelagic in 

 habit, frequenting the open sea at a distance from shore and near 

 the surface. It can be recognized by its size and by the very long 

 divergent caudal rami. 



Figure 134. — Halithale stria 

 croni: a, Femalo, fifth leg; 

 b, male, fifth leg (after 

 Sars). (From R. W. 

 Sharpe, Proc. U. S. Nat. 

 Mus., vol. 38, p. 418) 



