Glenendiaf Cyclepacen of 227 
“Genus 2. Seretta, Dana. Anterior antenna moderately long, slen- 
der, and not subcheliform in the male; posterior pair and prehensile 
feet nearly as in Arpactus ; short appendages to the first two joints of 
abdomen ; body slender, and two caudal’ sete much longer than the 
dy. (Two movable appendages under the beak.) 
The name Setella alludes to the seta-like form of the animal, and is 
from seta, a bristle. 
2. Palpi of the mandibles and of the mazille pronunent, and 
subnatatory. 
Family 3. Cananipe. External ovary single. Eyes two, the 
spherical lenses on the same or separate spots of pigment. An- 
terior antennze very long and slender, without an appendage. 
Abdomen abruptly narrower than the cephalo-thorax. (Marine 
Steet. ) 
‘a. Posterior thoracic legs rudimentary or obsolete, without appen- 
dages. Anterior antenne alike in the two sexes, and never with a 
geniculating joint, 
Genus 1. Catanus, Leach. Cephalo-thorax 4-jointed. Anterior an- 
tenne multiarticulate, with the front margin neatly setiferous, and also 
the posterior apices of the three terminal joints; first pair of feet much 
larger than the maxillipeds, having outward lateral motion, but scarcely 
prehensile ; maxillipeds very short and straight, setigerous; abdomen 
short, 2 to 4-jointed. Beak furcate. 
Genus 2. ScriBetta, Dana. Cephalo-thorax 4-jointed. Anterior 
antenne, long 7-jointed ; sete long and pointing in different directions. 
Maxillipeds much larger than the first pair of legs, flexed forward, the 
three terminal joints as long as the basal, and setigerous, the sete setu- 
lose. Abdomen very long, (as long as the cephalo-thorax ;) two sete 
to the short basal joint; (a plume or capillary appendage to base of the 
8 natatory legs, extending outward at right angles with the body.) 
Genus 3. Acartia, Dana. Anterior antenne few-jointed ; sete long 
and pointed i in different directions; maxillipeds much larger than the 
first pair of legs, not flexed, having the terminal joints very short, and 
setigerous nearly as in the genus Pontella; the first pair of legs small 
and short, not prehensile; the posterior thoracic legs, a single small 
joint bearing two divergent sete, one quite long, and usually standing 
out from. the 
The name Acartia is from @xegros unshorn, alluding to the long di- 
varicate hairs of the antenne. 
b. Posterior thoracic legs very long and nearly ai a antenne of 
the two sexes alike, without a geniculating joint. 
