54 ME. E. J. MIEES ON THE IDOTEID^. 



lateral angles. In the very large specimens from the Cape of 

 Good Hope the antennae are relatively shorter, the legs more 

 robust, and the posterior notch shallower, but this appears merely 

 to be due to the greater size and age of the specimens. In the 

 smaller specimens from the Cape these characters disappear. 



In a great number of New-Zealand specimens examined by 

 Mr. Thomson that naturalist found the length to vary from 1 to 

 over 2| inches (35 to 65 millim.), and the number of joints in the 

 antennal flagellum from 16 to 32. 



The Oniscus ungulatus of Pallas has generally been considered 

 to be synonymous with I. linearis, but the description and figure 

 agree far better with Idotea Lalandii. Pallas says that the head 

 is truncated anteriorly, the three anterior thoracic segments have 

 their poster o-lateral angles rounded, the posterior segments are 

 subimbricated, with acute angles. The epimera of the second 

 and third segments do not reach to the posterior margin of the 

 segment. There is a single distinct postabdominal segment be- 

 sides the terminal segment, which is marked on each side with a 

 double stria (or suture), and is excised and bideutate at its 

 posterior margin (^. e. with prominent postero-lateral angles). 

 Antennae of moderate size, 18-jointed ; in the figure they are 

 represented as very short, not reaching beyond the posterior 

 margin of the second thoracic segment, and the joints of the 

 peduncle short, scarely distinguishable from the flagellum. Pallas 

 gives the Indian Ocean as the locality of his specimens. 



Idotea eloistgata. 



Idotea elongata. White, List Crust. Brit. Mus. p. 95 (1847), sine desc. ; 

 Miers, Ann 8f Mag. Nat. Hist. (ser. 4) xvii. p. 225 (1876) ; Catalogue 

 of New-Zeal Crust, p. 93, pi. ii. fig. 3 (1876). 



Body elongate, almost linear, smooth, with the dorsal surface 

 very convex, so that the animal appears almost cylindrical in a 

 dorsal view. Head with the anterior margin scarcely excavated, 

 but with a slight depression in the middle between the anten- 

 nules ; antero-lateral angles not prominent. Segments of the 

 thorax (in the adult male) usually longer than broad, first seg- 

 ment with the antero-lateral lobes prominent and obliquely trun- 

 cated. Postabdomen about equalling the 3| posterior thoracic 

 segments in length, having usually indications of a lateral suture 

 on each side at some distance from the base of the terminal seg- 

 ment, which is rather depressed above, with subparallel sides, 



