THE IDOTEIIXS: 373 



tonotus is obvious ; but the antennules in CJicetilia are placed 

 immediately above the antennae, as in Edotia.' In Chcetilia 

 ovata, Dana, the sixth pair of legs are described as being 

 ' twice as long as the entire animal, terminating in a very 

 long bristle-like extremity, which consists of numerous 

 joints The seventh pair has also a multiarticulate ex- 

 tremity, which is, however, quite short.' Dana thought a 

 separate family ChaBtiliidas necessary for this genus. 



Ardurides, Studer, 1882, in general appearance and in 

 the length of the second antennas approaches Arcturus, but 

 the short-jointed limbs are all very nearly alike, though the 

 first are shortest, and the three following pairs a little 

 more prehensile than those to the rear. In the southern 

 Arcturides cornutus, Studer, the head has a pair of frontal 

 horns, and is not articulated with the first pereeon-segment 

 though divided from it by a suture. 



Idotea, Fabricius, 1798, has the second antennae mode- 

 rately elongate ; the maxilliped-' palp ' four-jointed, only 

 the last two joints being fused ; the limbs of the peragon 

 all nearly alike, with the sixth joint not or not much ex- 

 panded, but the seventh prehensile. The uropods have on 

 the basal plates a raised line near and almost parallel to 

 the inner margin, and an apical plumose seta, which is 

 concealed under the terminal plate. The species are very 

 numerous, and several additional genera have been pro- 

 posed which Mr. Miers does not think worthy to be 

 upheld. 



Idotea marina (Linn.) is the name he adopts for that 

 which Bate and Westwood describe as Idotea tricuspidata, 

 Desmarest, and Idotea pelagica. Leach, and which has also 

 been called by a dozen other names. It is very abundant. 

 Its distribution appears to be almost cosmopolitan. In 

 sizf and colour it is extremely variable. Idotea metallica, 

 Bosc, which seems to have as great a range over the world, 

 is, however, not recorded from British coasts. Idotea 

 emarginata, Fabricius. is common in British waters, but 

 not like marina on the shore, and the same may be said 

 of Idotea linearis (Linn.), with which Mr. Miers com- 

 bines the curiously striped Idotea sexlineata of Kroyer. 



