376 IDOTEA. 
ISOPODA. ARCTURIDA, 
NORMALIA. 
Genus—IDOTEA. (Fabdricius.) 
Generic character. Lower antenne with four thickened cylin- 
drical basal joints of moderate length, followed by a long multi- 
articulate flagellum ; first pair of legs not larger than the second. 
Pleon with two basal joints distinct, followed by a third semi- 
distinct. The four posterior ones fused into one common caudal 
plate. 
Turis genus (to which, with Professor Milne Edwards, 
we refer the Stenosome and Sidurie of Leach, and the Lep- 
tosome, Hebe, Oliske, Zenobie, and Armide of Risso) 
comprises an extensive series of species having the body 
more or less flattened and elongate, the head broadly 
truncate in front, the eyes small, lateral, and multi- 
faceted. The upper pair of antennz shorter than the 
head, and very slender, composed of four joints, of which 
the fourth is flattened, curved, and about the length of 
the preceding joint, but having the appearance of being 
composed of several articulations closely soldered to- 
gether; the lower pair of antenne rarely exceed half 
the length of the body, and are composed of five strong 
basal joints, with a long, slender, multiarticulate 
flagellum. ‘The parts of the mouth are protected in 
front by a large crustaceous lip (labrum), and behind by 
the large pair of foot-jaws, each of which consists of a 
strong basal stem, with an elongated lobe at its inner 
extremity (bearing a small style-like appendage on the 
middle of its inner edge), and with three large terminal 
joints, strongly ciliated along their inner margin and at 
