48 The Ottawa Naturalist. [June 



scattered in vast numbers over the roots of the lej^ume. When 

 they are not present, the clover, as regards its nitrogenous food, 

 is in the same category as other plants. The nitrogen elaborated 

 by these microbes is passed on to the host plant and there built 

 up into the usual nitrogenous compounds of the tissues of the 

 roots, stem and leaves. These facts, so briefly put, represent the 

 most important discovery in agricultural science of the nineteenth 

 century. 



For the reason that, as far as we know, the legumes alone 

 offer themselves as suitable hosts to these germs and are thus 

 able to appropriate nitrogen that is useless to all other vegetation, 

 they have been termed nitrogen-collectors. All other plants, in 

 contradistinction, are known as nitrogen-consumers. The legumes 

 are especially rich in nitrogen, and though we are unable to say 

 exactly what proportion of this element is taken by them 

 from the air by the means I have mentioned, we may be sure that 

 under favourable conditions the greater part is from that source. 



To he continued. 



THE LABRADOR FLYING SQUIRREL. 



By J. D. SoRNBORGER, Cambridge, Mass., U.S. 



Three specimens of Scinropterus , sent me by my friend Rev. 

 Walter W. Perrett, from Makkovik, Labrador, seem so different 

 from previously described forms, that I propose for them the name : 

 SciUROPTERUS SABRiNUS MAKKoviKENSis, new subspecies, the 

 Labrador Flying Squirrel. 



Both above and below, this form is the darkest of the flying 

 squirrels of eastern North America. The composition of its pre- 

 dominant colours, compared with those of a specimen from Moose 

 Factory, by means of the colour top,* is approximately : 



* The "colour top" made by the Milton Bradley Company, of Springfield, 

 Mass. See C. B. Davenport, Science, 1899, P- \^^ '■> A. G. Mayer, Proc. 

 Bost. Soc, V^ol. XXV'II, p. 246. This method of colour determination was 

 suggested to me by Prof. C. B. Davenport, now of the'Jniversity of Chicago, 

 and, though subject to many limitations, is, in most instances, far better 

 than any other method known to me. 



