276 Scientific Proceedings, Royal Dublin Society. 
sure that the present insect is distinct from that species, which is 
recorded from the Tschuktschi peninsula of northern Asia. The 
other allied species, J. sensibilis, was, until recently, known only 
from high northern latitudes, but it has lately been obtained both 
in Scotland (1) and Ireland. The mucro of I. brevicauda exactly 
resembles that of J. denticulata, Schaffer (4a), a north German 
form which, after examination of specimens kindly sent me by 
the describer, I believe to be a variety of J. sensibilis. 
The wide range of many species of Collembola is shown by 
the fact that three of the seven species mentioned in this Paper 
(Anurida granaria, Achorutes longispinus, and Lsotoma fimetaria) 
are inhabitants of Great Britain, one of them being found also in 
the southern hemisphere. The remaining four species—Lipura 
grenlandica, Achorutes dubius, Isotoma bidenticulata, and T. 
brevicauda must, for the present at least, be considered as charac- 
teristically northern species. No doubt, many more springtails 
remain to be discovered in the Franz-Josef archipelago, since 
seventeen species are already known from Spitzbergen, and 
sixteen from Greenland. In the accompanying table, I have 
indicated the distribution of the insects of the order as known 
from the principal Arctic islands. It is of interest to find that 
the presence of not a few species of these wingless insects in 
America, in Greenland, in the islands to the north of Hurope and 
Asia, and on the Kuro-Asiatic continent, lends support to our 
belief in a Pliocene or Pleistocene land connexion to the north of 
the Atlantic Ocean—a belief already upheld by so much evidence 
both geological and zoological. 
[| TaBLe. 
