ME. E. J. MIEES ON THE IDOTEIDiE. 39 



between low-coucave ; tlie body is not qnite as much narrowed be- 

 hind, and the flagellum of the outer antennae has but four or five 

 joints. It was obtained between Australia and Southern New 

 Zealaud, five hundred miles from Port Jackson, N. S. Wales. 



I have never observed any specimens of I, metallica with a 

 tridentate front. 



Idotea pustulata. 



Armida pustulata, Risso, Hist. Nat. Eur. merid. v. p. 110 (1826). 



This species is apparently allied to I. metallica and I. ocJioiensis. 

 It is described as follows : — " Body of a deep bluish grey, with all 

 the segments acute on the sides ; head pustulated ; eyes black : 

 the first four joints of the antennae elongated, the fifth longer, the 

 others very short ; the four joints of the antennules as long as the 

 two first antennal joints ; ' palpi ' pectinated ; legs somewhat 

 roughened ; segments of postabdomen narrow, the last carinated, 

 almost truncated at apex." Length about 1 inch (25 millim.), 

 breadth rather more than i inch (7 millim.). 



It is apparently distinguished from I. metallica by the longer 

 peduncular joints of the antennae and the carinated terminal 

 segment, wherein it resembles I. ochotensis ; but whether it be 

 really distinct could only be determined by examination of spe- 

 cimens. It is probably the species referred to by Hope (Cat. 

 Crust. Ital. p. 26, 1851), without description, under the designa- 

 tion Armida puncfulata, B/isso. 



? Idotea lacusteis. (Plate I. figs. 11 & 12.) 

 Idotea lacustris, Thomson, Trans. New-Zeal. Inst. xi. p. 250 (18/9). 

 Is described by Mr. Thomson as having the body narrow- 

 elliptical, little more than twice as long as broad ; front of head 

 excavated, not toothed ; first segment of thorax somewhat longer 

 than those succeeding, which are subequal ; postabdomen three- 

 jointed, terminal joint (formed of three coalescent segments) 

 hardly narrowing to the rounded extremity ; antennules not 

 half as long as the base of the antennap, 4-jointed, joints sub- 

 equal ; antennae one third as long as the body ; flagellum 9-11- 

 jointed, with a dense fringe of very short setae o]i the outer 

 margin ; epimera nearly square, the last three slightly produced 

 posteriorly. Colour dark grey mottled with browu, with a duller 

 median band extending from the head to near the extremity of the 

 ])Ostabdomen. Length f inch. 



