184 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
CORYNTJRA Brady. 
Fifth thoracic segment and abdomen of male symmetrical. Anterior antenme of female 17-jointed : 
long bristles with lamelliform margin. Posterior antenna', with rami of nearly equal length ; terminal 
joints of outer ramus abortive, scarcely distinguishable. Mandibles with elongated second basal joint, 
with end of which the rami articulate. Maxilla consisting only of first basal, with the very bristly 
first and second inner lobes. Proximal lobes of anterior qjaxillipeds minute. Posterior maxilliped 
3-jointed. Inner ramus of first pair of feet 2-jointed. Fifth pair of feet of female without inner 
ramus, sometimes asymmetrical. 
Female: Cephalothorax with 5 to 6 segments, according as last two thoracic segments are fused 
or separate; a large median eye, without lens; rostrum wanting, in front of upper lip a horseshoe- 
shaped fringed lamella. Abdomen with 2 to 3 segments, asymmetrical, sometimes twisted About 
longitudinal axis. Anterior antennae resembling those of Acartia, 17-jointed, with joints 1 to 7, 9 and 
10, 24 and 25 fused. Posterior antennae resembling those of Parapontella, but outer ramus with 
completely abortive distal joints. Mandibular blade usually rather narrow, with 5 teeth; outer 
ramus scarcely jointed. Maxillipeds similar to those of Parapontella , but proximal lobes of anterior 
pairs are more decidedly reduced and inner ramus of posterior pair shorter and 1-jointed. First to 
fourth pair of feet with 3-jointed outer and 2-jointed inner rami; first basal joint with an inner 
marginal bristle on all four pairs; second basal joint without a bristle on first, with a plumose outer 
marginal bristle on the fourth pair; bristles of rami as follows: Outer ramus of first pair with 0, 0, 1 
(2) outer and 1, 1, 4 inner marginal bristles; second to fourth pairs with 1, 1, 3 outer and 1, 1,5 inner 
marginal bristles ; inner ramus of first pair with 0, 1 outer and 3, 5 inner marginal bristles, of second to 
fourth pairs with 0, 1 outer and 3, 6 (5) inner marginal bristles. Fifth pair strongly abortive, 
consisting of a common median piece and a couple of 2-jointed, not always symmetrical, feet. 
Male (known only in few species) : Sexual differences in structure of abdomen, right anterior 
antenna, and fifth pair of feet. Abdomen with 5 segments; genital orifice siuistral. In right ante- 
rior antenna sixth and seventh joints are separate from fused first to fifth, and the ninth is separated 
from tenth; the middle joints are more strongly dilated than in Acartia, and, as in that genus, the 
nineteenth to twenty-first and the twenty-second to twenty-fifth joints are fused. Fifth pair of feet 
resembles that of Acartia , but consists (besides middle piece) of 3 joints on either side, the left being 
the longer. 
21 . Corynura bumpusii new species. 
Male: Body long and slender; separation between fourth and fifth thoracic segments not very 
pronounced, latter symmetrical, with rounded posterior corners. Abdomen consisting of 5 segments, 
its tip turned to right side and slightly twisted about longitudinal axis ; first segment somewhat asym- 
metrical, with a rounded projection on left posterior corner; second with a similar but much more 
prominent and pointed outgrowth on right side; third and fourth segments of nearly equal length; 
fifth not half as long as fourth. Furca asymmetrical, its right limb distinctly longer than left, 
conspicuously constricted near base; inner edges of limbs fringed with delicate hairs ; outermost bristle 
on the right side enlarged, blade-shaped, with a short, conical, dorsal, tooth-like projection a short 
distance beyond its base ; innermost bristle slender, nearly as long as first bristle. Relative lengths of 
bristles 4<1<3<)2. 
Eye large, without dorsal lenses. Rostrum absent, front of head evenly rounded in profile; 
mouth surrounded in front by a horseshoe-shaped, fringed lamella. Anterior antenme reaching only 
to posterior edge of third abdominal segment; right anterior antenna not much widened in middle 
(joints 13 to 17), poorly furnished with bristles; joints 17, 18, 19 to 21 with delicate pectination; 
joints 22 to 25 fused, and bearing at tip 5 long plumose bristles. The long bristles on joints 14, 16, 
21, and 24 provided along one edge with a very delicate, transparent lamina, often slightly sinuous in 
outline (effect of formalin?). Posterior antenn* with long, slender rami; first joint of inner ramus 
fused with second basal joint and bearing on its distal margin a short dense series of graduated 
spines; second joint with a few hairs in corresponding position ; first joint of outer ramus very short; 
second joint reaching to middle of slender second joint of inner ramus; outer ramus terminates in 
4, the inner in 6 long plumose bristles. 
- Mandibular blade with 5 teeth gradually decreasing in length from first, which is separated from 
second by a considerable diastema; second basal joint slender, fully 4 times as long as wide, rami 
inserted at same level on its tip, outer ramus but little longei than inner, the former with 5, the latter 
