MB. E. J. MIEES ON THE IDOTEIDiE. 57 



more acuminated at its distal end, and the posterior epimera are 

 small. 



This species in external form nearly resembles I. stricta, Dana, 



with which I should have considered it identical, but for the bi- 



■ articulate postabdomen, the terminal segment of which is marked 



near its base with two sutures. The antenual flagellum is more 



numerously jointed. 



The description is taken from examples in the Museum collec- 

 tion, which I have compared with the Paris type. They scarcely 

 diifer from the description of Gruerin-Meneville, except in the 

 longer antennae, whose flagellum is nearly always longer than 

 the peduncle. 



In the brood-pouches of some of the females from Flinders 

 Island are numerous young examples, about -^inch (4 millim.) in 

 length. 



Idotea lobata. (Plate II. figs. 8 & 9.) 



Idotea lobata. White, List Cr. Brit. Mus. p. 96 (1847)3 descript. milia. 



In this remarkable species the body is elongated and moderately 

 convex, the segments of the thorax are laterally produced, and 

 with the greatly developed epimera form lateral prolongations 

 that are perfectly distinct from one another even at their bases, 

 and are more or less rounded at their apices. The head has its 

 frontal margin nearly straight, and'its antero-lateral angles are 

 not prominent. The thoracic segments are short and nearly 

 smooth above. The postabdomen about equals the four posterior 

 thoracic segments in length ; the terminal segment has straight 

 and subparallel sides, and is emarginate at its distal extremity, with 

 the postero-lateral angles rounded. Eyes large. Tlie antennules 

 apparently reach almost to the extremity of the penultimate pedun- 

 cular joint of the antennae, and have their basal joints moderately 

 dilated. Antennae short, when retracted not reaching beyond 

 the posterior margin of the fourth thoracic segment, with the 

 last two joints of the peduncle subequal, short, but longer than 

 the preceding ; flagellum with about 10 joints. The epimera, in a 

 dorsal view, are large and occupy the whole of the lateral margins 

 of the produced thoracic segments. Legs slender and nearly 

 naked. Terminal plates of the opercular valves four-sided, but 

 little longer than broad, w'ith the distal ends truncated. Length 

 rather more than j inch (10 millim.), breadth nearly ^ inch 

 (4 millim.). 



