FREE-SWIMMING COPEPODS OF THE WOODS HOLE REGION. 
161 
A 17, 
A 18, 
A 19, 
A 20. 
A 21. 
A 22. 
A 23. 
B. 
B 1. 
B 2. 
B 3. 
C. 
C 1. 
C 2. 
Ceplialothorax and abdomeu flattened, leaf-shaped; mandibles, maxilla? and anterior maxilli- 
peds lacking or reduced to minute stumps ; furca very long and rod-shaped Copilia £ 
Ceplialothorax of varying form, rounder or sometimes depressed in cross section, but never leaf- 
shaped; cephalic appendages all present; furca shorter, at most 6 times as long as broad. .A 18 
Outer ramus of first foot 1 -jointed; posterolateral corners of the four cephalothoracic seg- 
ments and front drawn out into processes Clytemnestra 
Outer ramus of first foot 2 to 3-jointed A 19 
Outer ramus of posterior antennae 1-jointed; furca very short, on either side with 1 very long 
bristle (at least twice as long as trunk) ; limbs of furca and the 2 bristles fused in median 
line ; remaining furcal bristles obsolescent JEgisthus $ 
Outer ramus of posterior antennae 3-jointed, thin; furca short, with separate limbs and on 
either side with one long bristle, at least as long as trunk and at least twice as long as any 
of remaining bristles *MicrosetelJa 
Outer ramus of posterior antennae lacking; furca longer than broad, with separate limbs.. A 20 
Anterior and posterior maxillipeds of similar structure, both of them provided with long prickly 
bristles *Oitliona 
Posterior maxilliped with few (or no) short bristles and'a terminal hook (Onccridce) A 21 
Fifth pair of feet 1-jointed, each terminating in 2 lanceolate appendages, which are provided 
with denticulate edges; cephalothorax long and slender Lubbockia 
Fifth pairof feet 2-jointed, 1-jointed, or button-shaped, provided with naked or plumose bristles; 
cephalothorax less slender A 22 
Anterior antennae with very long and robust aesthetasks (sense hairs) on terminal joint; fifth 
pair of feet 2-jointed Ratania 2 
Anterior antennae with numerous penicillate aesthetasks on proximal joints; fifth pairof feet 
papillate ; cephalothorax robust, pear-shaped Pachysoma 
Anterior antennae with few and very delicate aesthetasks; fifth pair of feet small rods or knobs, 
sometimes reduced to a pair of bristles A 23 
Hooked bristles on terminal joint of posterior antennae of medium length; inner ramus of pos- 
terior feet at least as long as the outer ramus, its terminal joint in the fourth pair at least 
li) times as long as first and second together * Onccea 
Hooked bristles on elongated terminal joint of posterior autennae very long; inner ramus of 
posterior feet shorter than outer ramus, its terminal joint in fourth pair not longer than 
either of the two proximal joints l Conaa 
Head without dorsal ehitinous lenses or lateral hooks B 1 
Head with 1 or 2 pairs of ehitinous lenses and hook on either side of lateral border B 3 
Posterior maxilliped 4-jointed; mandible with the rudimental outer ramus articulating proxi- 
mally before the middle of second basal joint; rami of the posterior antennae of nearly equal 
length Parapontella 
Posterior maxilliped 5 to 7-joiuted; mandibular rami articulating with second basal joint at 
about same level; outer ramus of posterior antennae much shorter than inner ramus B2 
Abdomen with asymmetrical protuberances * Monops 
Abdomen symmetrical (except in fusion of right furcal limb with anal segment in the 
female) Pontellina 
Head with one pair of dorsal eye lenses; base of rostrum with lenticular thickening * Ponte 
Head with two pairs of dorsal eye lenses; the base of the rostrum without lenticular thick- 
ening * Anomalocera 
Posterior antennae biramous; outer ramus with several joints; -first abdominal segment with- 
out rudiments of feet; anterior autennae at least 15-jointed ( Gymnoplea in part) C 1 
Posterior antenna? either uni- or bi-ramous; in the latter case with small, 1-jointed outer ramus; 
first abdominal segment with rudimental (rod- or leaf-shaped) feet; anterior antennae at most 
9-joint,ed. (Ampharthrandia in part) C 7 
Both feet of fifth pair biramous, rami 2- or 3-jointed Leuckariia 
Fifth pair of feet absent, or, if present, not more than left foot biramous C 2 
Furca long and narrow, at least 6 times as long as broad; terminal bristle of third joint of 
outer ramus of second to fourth foot denticulate *Temora 
Furca, at most, 3 times as long as broad; terminal bristle of third joint of outer ramus of 
second to fourth foot with a smooth border C 3 
F. C. B. 1899—11 
