FREE-SWIMMING COPEPODS OF THE WOODS HOLE REGION. 
175 
between the proximal joints in both rami of the female is obliterated, whereas outer ramus usually 
remains 3-jointed in the male. Fifth pair of feet rudi mental in the female, 3-jointed on either side; 
in male, on the left, 4-jointed, foreipate; on the right, 3-jointed, uncinate. Grasping antenna ofmale 
on right side. 
Female: Cephalothoras consisting of 5 segments; last two thoracic segments fused; rostral 
filaments soft. Abdomen with 3 segments; furca long, narrow, and sometimes asymmetrical. 
Anterior antennae with delicate Eesthetasks and short, flaccid bristles on anterior maigin. 1 osterior 
antennae similar to those of Centropages, but outer ramus is more slender and with a shorter 
end joint. Mandibular blades voluminous. The succeeding 3 p airs of appendages resembling those 
of G alarms, anterior maxilliped with long lobes. First pair of feet with 3-jointed outer ramus and 
2-joiuted inner ramus (first and second joints CQalesced) ; in second to fourth pairs the articulation 
between the two proximal joints of both rami has disappeared; first basal joint in second to 
fourth and usually also in first pair 
with a plumose inner marginal bristle. 
Bristles in rami as follows : In first pair 
outer ramus with 1, 1, 2 outer and 1, 1, 4 
inner marginal bristles; in second to 
fourth pairs outer marginal bristles 1, 1, 
3, inner 1, 1, 5 ; inner ramus of first pair 
with 0, 1 outer, 1, 5 inner marginal bris- 
tles; second and third pairs with 0, 0, 1 
outer, 1, 2, 5 inner marginal bristles; 
fourth pair with 0, 0, 1 outer, and 1, 2, 4 
inner marginal bristles. 
Male : Sexual peculiarities in struc- 
ture of trunk, of right anterior antenna, 
and in feet, especially those of fifth 
pair. Last thoracic segment asymmet- 
rical; abdomen consisting of 5 seg- 
ments, the genital opening sinistral. 
Grasping antenna dextral, similar to 
that of Centropages; the articulation 
between the eighteenth and nineteenth 
joints; joints 19 to 21, 22 to 23, 24 to 25 
fused. Outer ramus of feet sometimes ’■ 
2-jointed in left foot of second pair, 
otherwise 3-jointed. 
Length of female, 1 to 1.5 mm.; of 
male, 1 to 1.35 mm. 13. T emora i on gi C ornis O.F.Miiller; a, female, dorsal aspect; 6, male, dor- 
13 . Temora longicornis O. F. Muller. sal aspect; c, male, distal portion of right anterior antenna; d, male, fifth 
' s ’ ' pair of feet; e, female, fifth pair of feet. 
Lateral corners of last thoracic seg- 
ment rounded; furca symmetrical; f'urcal bristles short, none of them as long as furca, outermost 
bristle near tip of outer margin, second bristle slightly thickened at its base. Joint 17 of grasping 
anteuua not pectinated ; number of appendages on proximal joints of grasping antenna differing some- 
what from those on left. First basal joint of first foot without an inner marginal bristle ; second and 
fourth foot symmetrical, even in male; inner marginal prong on terminal joint of fifth foot of female 
somewhat shorter than two terminal prongs; terminal joint of left fifth foot in male irregularly 
rod-shaped. 
A very common species in tow taken from the Fish Commission’s wharf at Woods Hole. A glance 
at the tow collected throughout the year by Mr. Edwards shows that the species is much more abun- 
dant during winter than summer. During July and August, 1899, it was rarely seen. It is au 
essentially boreal form as shown by the list of localities given by Giesbrecht. 
METRIDIA Boeck. 
Closely related to Pleuromma ( q . v.), but without lateral pigmented knob; terminal saw of outer 
ramus of third pair of feet of normal structure; feet of male (especially those of second pair) agreeing 
with those of the female. Furca 2 to 5 times as long as broad. 
