Chilton. — On Neir Zealand Idoteidue. 199 



beyond the posterior margin of the fourth thoracic segment. 

 Legs very slender. Epimera scarcely visible in a dorsal view ; 

 in a lateral view they are narrow, linear, and the last pair only 

 reach to the posterolateral angles of the segment with which 

 they are articulated. Terminal plates of the opercular valves 

 somewhat longer than broad, four-sided, with the distal ends 

 truncated or very slightly emarginated. Length of a full-sized 

 male about 2in. (50mm.) ; breadth about ^in. (7mm)." — 



[MiEBS.] 



All the specimens that I have seen were brown in colour 

 when alive, and were found on brown seaweeds. 



My specimens, of which I have a fair number from 

 Lyttelton, Akaroa, and Brighton near Dunedin, agree well 

 with Miers's description as given above. In some specimens 

 the postabdomen is almost uniarticulate, the dividing-mark 

 being very indistinct ; the epimera are difficult to make out, 

 and are usually more or less completely anchylosed with 

 their respective segments. In the female, which has been 

 described as Eclotia dilatata by Mr. Thomson, the thorax 

 is " much dilated in the middle, the second, third, and 

 fourth segments being progressively broader and bluntly 

 angled at the sides, fifth suddenly narrowing to less than 

 half the width of the fourth." In the adult female the 

 plates forming the broad pouch arise from the second, 

 third, fourth, and fifth segments of the thorax. I have one 

 specimen, apparently a young female, with plates of fairly 

 large size on the fifth segment, and very slight indications of 

 plates on the second, third, and fourth ; and in this specimen 

 the thorax is slightly broadened. 



The depth of the notch at the end of the postabdomen 

 varies to some extent. Miers describes it as "a moderately 

 deep rounded notch ; " in many of my specimens it might be 

 called a " shallow notch ; " but, again, in Mr. Thomson's type- 

 specimen of Edotia dilatata the notch is deeper : the postero- 

 lateral angles are rounded ; in Mr. Thomson's figure '•• they 

 are shown rather more acutely than they should be. 



Idotea pekonii. 



Idotca pero7iii, M.-Edw., "Hist. Nat. Crust.," iii., p. 133 

 (1840); Miers, "Jour. Linn. Soc. Zoology-," xvi., p. 55, 

 pi. ii., figs. 6 and 7 (1881). 



Idotea stricta, Dana, "U.S. Expl. Exped.," xiv., Cr. ii., 

 p. 704, pi. xlvi., fig. 7 (1853); Miers, "Jour. Linn. Soc. 

 Zoology," xvi., p. 62 (1881). 



Idotea ca^idacuta, Haswell, " Proc. Linn. Soc. N.S.W.," 

 vi., p. 1, pi. iv., fig 4. ; " Cat. Aust. Crust.," p. 276 (1882). 



"Body narrow-oblong rather than oval, not carinated, 



* hoc. cit.y pi. xii., fig. 9. 



