286 Biblio(jraphical Notice. 



exist, or exists only in an insufficient degree. The description 

 of these experiments being too long to find a place in a sum- 

 mary, I shall conclude with a statement of the process which I 

 have seen employed by the Argyroneta when it wished to 

 convey from the surface a supplementary mass of air, destined 

 either for the formation of its dwelling, or for the renewal of 

 the air in the latter. When the Argyroneta is examined with 

 the lens, we easily see that its posterior femora are furnished 

 with thick hairs. If, now, we surprise the animal when it is in 

 search of a supplementary mass of air, we find that at the 

 moment when it is about to quit the surface of the water it 

 separates its posterior femora pretty widely, and that, when it 

 dives, a comparatively large gaseous mass on each side of the 

 abdomen unites the ordinary stratum of air to the inner surface 

 of the femora. In swimming to regain its dwelling, the animal 

 only employs the movements of its anterior limbs. What then 

 takes place in the cell or in the nest I have been unable to 

 ascertain ; but we may suppose that the spider applies the 

 femora to its body, and thus throws ofiF the portions of air of 

 which I have just been speaking. In any case, when the 

 Argyroneta again quits its cell or its nest, its posterior legs are in 

 their normal position, and the quantity of air entangled between 

 them and the abdomen is insignificant. 



BIBLIOGRAPHICAL NOTICE. 



Contributions towards a Cybele Hihernica, being outlines of the 

 Geographical Distribution of Plants in Ireland. By D. Moore, 

 Ph.D., and A. G. More, F.L.S. Dublin, 1866, pp. 56, 399. 



The title of this work, * Cybele Hibernica,' will at once inform our 

 readers of its primary object. It is an attempt to do for Ireland 

 what Mr. H. C. Watson performed for Great Britain in his * Cybele 

 Britannica ; ' and the authors have succeeded in doing this far 

 more completely than they themselves seem inclined to allow. The 

 country is divided into twelve botanical districts in such a manner 

 as to mark, as far as possible, the pecuHarities of the flora : three are 

 central and do not touch the seacoast at all ; the others all contain 

 a considerable extent of coast : two are western, so as to include the 

 peculiar Atlantic plants of Kerry, Galway, and Mayo. These 

 districts were first proposed by Prof. C. C. Babington in a paper 

 read to the Dublin University Zoological and Botanical Association 

 and published by it ; but he has there, perhaps unadvisedly, at- 

 tempted to divide these ** provinces," as he calls them, into more 

 minute districts. Apparently our authors have done well in making 

 his provinces their districts and neglecting, at least for the present, 

 the smaller subdivisions pointed out in that paper. 



