92 STALK- AND SESSILE-EYED CRUSTACEA 
96. Idotea argentea. 
Idotea argentea, Dana, U.S. Explor. Exped. xiv, Crust. part i, 
p- 698, pl. xlvi, fig. 1, (1853). 
? Idotea compacta, List. Crust. Brit. Mus. p. 95, (1847), sine descr. 
Long sub-elliptical, truncate or slightly excavate in front ; surface 
even and smooth, epimerals rather broad, entire. Abdomen broad 
oblong, a little narrower behind, and broad truncato-rotund at apex. 
Eyes prominent, situated on the angles of the head. Inner antenne 
_ hardly half as long as base of outer, last joint as lone as two preceding, 
very minutely setulose on the outer side. Outer antenne nearly half 
as long as the body, flagellum seven-jointed, and shorter than the base, 
sete minute, and rather few. Colour silvery, with a bluish shade, 
which is deeper towards the sides. Length five lines. (D.). 
New Zealand? (Dana). 
Dana considers that.a specimen six lines long, which he obtained 
near New Zealand, and which differs in| having the flagellum of the 
outer antenna about as long as the base and eight-jointed, surface 
minutely scabrous under a high magnifier, probably belongs to this 
species, 
The specimens in the Collection of the British Museum, which I 
refer with some doubt to this species, have the body broadest in the 
middle, somewhat approaching the form of Edotea, and the terminal 
segment of the abdomen usually, but not always, marked with a white 
band on its posterior margin. Length 3 in, 
There are specimens from the coast of New South Wales, and one 
from Borneo, in the Collection. The latter was named by White J. 
compacta, in the List of Crustacea in the British Museum. 
Idotea margaritacea, (Dana, U.S. Explor. Exped. Crust. part u, 
p- 700, pl. xlvi, fig. 2); has the three teeth of the front very low; one 
in either angle, the third less distinct, in the middle of the front, the 
outer subacute, the spaces between low concave. Inner antennae 
extending to apex of antepenultimate joint of base of outer antenna, 
with a few short sete at apex on either side. Outer antenne with the 
flagellum but four or five-jointed. Surface of the joints very minutely 
scabrous when seen under a high magnifier, Colour bluish, with the 
back pearly white. It was obtained between New-Holland and Northern 
New Zealand, and differs from the preceding somewhat in its antenne 
and front of head; and the body is not quite so much narrowed behind. 
I think that it is probably only a variety of L. argentea. 
