188 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
24. Setella gracilis Dana. 
This single strongly marked species should include, according to Geisbrecht, besides S. gracilis 
Dana, some four other forms regarded by Dana as distinct species, also Mirada gracilis Dana, Setella 
tenuis Lubbock, and S. messinensis Claus. In color tbe chitin of body and of proximal portions of 
limbs is transparent violet; gut ferruginous 
red surrounded by oil drops which are colorless 
or yellowish and usually darker in tbe oral 
region; eye ruby-red. 
Length of female, 1.4 to 1.5 mm. ; of male, 
1.16 to 1.3 mm. 
Several specimens, many ovigerous females 
and a few males, were taken in Gulf Stream, 70 
miles south of Marthas Vineyard, July 25, 1899. 
MIRACIA Dana. 
Male: Cephalothorax with 4 segments 
(head fused with first thoracic), abdomen with 
6 segments; head and first thoracic segment 
laterally compressed, with two large chitinous 
lenses on front; furca rather long. Anterior 
antennae grasping organs, 9-jointed, articula- 
tion between tbe sixth and seventh joints; 
bristles short, one aesthetask on fourth joint. 
Posterior antennae 3-jointed (second basal joint 
fused with first joint of inner ramus), with 
very small, 1-jointed outer ramus. Mandible 
(like succeeding limbs) small, with rudimental 
rami and denticulate blade. Posterior maxil- 
liped elongated, rod-shaped, 2-jointed, with 
short terminal hooks. Feet elongated ; outer 
ramus 3-jointed; inner ramus of first and sec- 
ond pairs 2-jointed, of third and fourth pairs 
3-jointed ; inner ramus of second pair of peculiar 
structure; fifth pair of feet rudimental, leaf- 
shaped. 
Female: Differs from male (according to 
Brady), in fusion of first and second abdominal 
segments, in structure of 8-jointed anterior 
antennae, of 3-jointed, normally constructed 
inner ramus of second pair of feet, and in fifth 
pair of feet. 
25. Miracia efferata Dana. 
Some 30 specimens of both sexes of this, 
the only species of the genus, were taken in the 
Gulf Stream about 60 miles south of Marthas Vineyard, July 28, 1899, late in the afternoon. The 
female is dark greenish-blue, more yellowish along edges of segments, with a large black spot on 
bead, becoming blue over the eyes. There is a glistening metallic luster to upper surface of bod^ . 
Eggs blue or red. '1 be male is much paler than female. 
Length of female, 1.75 to 2 mm. ; of male, 1.5 mm. 
24. Setella gracilis Dana ; a, female, from tbe left side ; i>, male, 
anterior antenna; c, male, fifth foot: d, female, filth foot. 
CLYTEMNESTRA Dana. 
Female: Cephalothorax with 4 segments (head and first thoracic fused), abdomen with 5 segments 
(first and second abdominal fused); postero-lateral corners of segments in flattened cephalothorax 
prolonged into projections; furca short. Anterior antennae 7 or 8 jointed, with short bristles and 
long aestlietasks. Posterior antennae 3-jointed (first and second basal joints fused), with rudimental 
