376 IDOTEA. 



/ SO POD A. ARCTURID^fi. 



NOR MALI A. 



Genus IDOTEA. (Fabricius.) 



Generic character. Lower antennae 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. 



THIS genus (to which, with Professor Milne Edwards, 

 we refer the Stenosomce and Sidurice of Leach, and the Lep- 

 tosomce, Hebe, Oliskce, Zenobia, and Armicks 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 antennae 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 antennae 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-jaw r s, 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 



