8 NATURAL SCIENCE. January. 



It is, no doubt, very difficult to obtain direct and conclusive 

 evidence of such cases of wild hybridisation as may occur, but it may 

 be remarked that of thousands of specimens that have passed under 

 the writer's ken during the last twenty years, only one single 

 individual could be at all confidently presumed to be a hybrid, and 

 in that case, just as in this, the occurrence took place in a district 

 where, owing to much shooting down of game, one or both parents 

 might have found much difficulty in finding a mate of their own 

 species. 



Where this difficulty does not exist, owing to the abundance of 

 both forms, there seems, as yet, no evidence that crossing ever takes 

 place among mammals in a state of Nature, whatever may be the case 

 with birds. But the very absence of such evidence makes it the more 

 important that every apparent case should be properly investigated, 

 and we are therefore very grateful to have Dr. Lonnberg's careful 

 account of the Bastard Swedish Foxes. 



The paper is illustrated by an excellent figure of one of the 

 hybrids, showing very clearly how intermediate in colour it is between 

 the two parent species. 



The Biology of the Great Lakes. 



In connection with Mr. Scourfield's plea for a British fresh-water 

 biological station, appearing in this number, it is very instructive to 

 note the increasing attention paid to the study of fresh-water animals 

 and plants in the United States. As a good instance of this may be 

 taken the work of the Michigan Fish Commission. This Commission 

 not only performs the practical duties of fish-hatching and "planting," 

 but has also carried out a considerable amount of valuable biological 

 work, as may be seen from the six Btilletins it has already issued. The 

 ultimate object in view has naturally been a practical one, namely, to 

 ascertain the cause of the decreasing yield of whitefish {Coregonns 

 clupeifonnis) in spite of artificial propagation, evidently a subject of 

 some importance to the State of Michigan, touching as it does four of 

 the five Great Lakes. Recognising that the only basis for intelligent 

 action in the future would be a more complete knowledge of all the 

 conditions surrounding the whitefish, the Commission very wisely 

 began a biological examination of the Great Lakes. During the 

 summer of 1893 ^ party of naturalists, under the direction of Professor 

 J. E. Reighard, was maintained on Lake St. Clair, a great spawning- 

 ground of the whitefish, lying between Lake Huron and Lake Erie, 

 and in the following year a similar party, under Professor H. B. Ward, 

 was stationed at Charlevoix on Lake Michigan. In both instances 

 every effort was made to get as complete a picture as possible of the 

 whole aquatic fauna and flora. Most of the groups of any importance 

 were worked out by specialists, whose reports, published either as 

 separate Btilletins or as appendices to the two principal reports 

 {^Btilletins Nos. 4 and 6), contain a mass of information, of use not only 



