326 A HISTORY OF RECENT CRUSTACEA 
tioned as of special importance. For more recent infor- 
mation the student should consult Sars’s two papers on the 
‘Isopoda Chelifera’ published in 1880 and 1886, and that 
by Norman and Stebbing on the Isopoda of the Liyhtning, 
Porcupine, and Valorous Expeditions, in the ‘ Transac- 
tions of the Zoological Society’ for the latter year. The 
Jast-mentioned paper enumerates thirteen genera and 
forty-six species of Tanaide as occurring in the North- 
Atlantic and Mediterranean, T'yphlotanais and Leptognathia 
being each credited with ten species and Leptochelia with 
five. 
Tanais tomentosus, Kroyer, 1842, has been identified 
with Yanais vittatus (Rathke), 1843. In Devonshire 
in timbers washed by the tide it occurs in company 
with Limnoria lignorum and Chelura terebrans. In 
America the same association is reported of Tanais filum, 
Stimpson, which may, however, be a Leptochelia. The 
Egyptian species, Tanais Dulongii (Audouin), is by Bate 
and Westwood enrolled in the fauna of Devonshire, though 
their only specimens came from Polperro, in Cornwall. 
They are with some reason doubtful about the identifica- 
tion, and the rediscovery of their species in Great Britain 
is still awaited. They curiously include in the synonymy 
the Tanais Dulongit of Thompson and of White, though 
acknowledging in the text that these Irish specimens had 
proved to be mutilated Amphipods. They speak of the 
third perzeopods, or fifth pair of trunk limbs, in this 
species as carrying branchial organs, which would be a 
peculiarity of no little importance, were it not practically 
certain that the supposed branchieze were merely the mar- 
supial plates of a female specimen. 
The species which Bate and Westwood name Leptochelia 
Hidwardsii (Kroyer) should rather be called Leptochelia 
Saviqnyi (Kroyer), as the earlier description belongs to 
that name. Kréyer’s Tanais Edwardsii is the male of the 
same species. Leptochelia algicdla, Harger, from New Eng- 
land, is, according to Sars, in the female a synonym of this 
species. while in the male it is a synonym of Leptochelia 
dubia (Kroyer). Fritz Miiller, and after him Dr. Dohrn, 
