320 A HISTOKY 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 Lightning, 

 Porcupine, and Valorous Expeditions, in the ' Transac- 

 tions of the Zoological Society ' for the latter year. The 

 last-mentioned paper enumerates thirteen genera and 

 forty-six species of Tanaidse as occurring in the North- 

 Atlantic and Mediterranean, Typhlotanais and Leptognaihia 

 being each credited with ten species and Leptochelia with 

 five. 



Tanais tomentosus, Kroyer, 1842, has been identified 

 with Tanais 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 Dulongii of Thompson and of White, though 

 acknowledging in the text that these Irish specimens had 

 proved to be mutilated Aniphipods. They speak of the 

 third pergeopods, 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 branchias were merely the mar- 

 supial plates of a female specimen. 



The species which Bate and Westwood name Leptochelia 

 Edwardsii (Kroyer) should rather be called Leptochelia 

 Savignyi (Kroyer), as the earlier description belongs to 

 that name. Kroyer's Tanais Edwardsii is the male of the 

 same species. Leptochelia algicola, 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, 



