IDOTEA LINEARIS. 389 
Idotea diodon. Latreite, Nouv. Dict. d’Hist. Nat. xvi. DealOo; 
Guérin Mé&vy., Exp. Morée, p. 49. 
Idotea viridissima. Risso, Crust. de Nice, p. 136, pl. 3, fig. 8. 
Idotea hectica. Leacu, Edinb. Ene. vi. p. 404. 
Stenosoma hecticum. Lwacu, Linn. Trans. vii. p. 433. 
Oniscus ungulatus. Pauuas, Spic. Zool. 9, 62, tab. 4, f. 11 (antennis 
falsis 2) 
Tuts large species is at once distinguished by its parallel 
and sub-depressed form, and the very robust joints of the 
peduncular portion of the lower antennz, which organs 
are nearly as long as the whole body; the flagellum ter- 
minated by two very minute articuli (c. x.) ; the front 
margin of the head is strongly sinuated, with the lateral 
lobes elevated; the upper surface of the whole animal 
isuneven. The second, third, and fourth segments of 
the body exhibit a small portion of the epimera-like 
base of the legs at their anterior angles, whilst the fifth, 
sixth, and seventh joints have the posterior angles cut off, 
and replaced by the same portion of the legs. The first 
two segments of the tail are quite distinct, but the third 
is only separated from the large terminal segment at the 
sides, being completely soldered with it in the middle ; the 
legs gradually but slightly increase in length, from the 
first to the seventh pair, each being armed with a long 
and strong simple hook-like finger. The tail occupies 
one-third of the entire length of the animal. 
The operculum reaches to the posterior margin of the 
caudal segment, and has the second joint narrower than 
the first, and terminating in a rounded extremity. 
This species occurs in many parts of the British coast. 
We have received specimens from Cumbray from Mr. 
Robertson; from Guernsey, Falmouth, and the coast of 
Durham from the Rev. A. M. Norman; and we have 
dredged it in Bigbury Bay, near Plymouth, on which 
coast it is by no means common. 
