MB. W. D. CEOTCH ON THE LEMMING. 157 



Hydrocissa alhirostris treats Sparrows in the same nnanner. 

 The day before yesterday [letter being dated Nov. 24i, 1876] I 

 found Aceros subrvficollis discussing a rare Lory. I don't think 

 that the habit is abnormal ; for both birds manifest it and try to 

 catch the smaller birds as they fly past. They are also very well 

 cared for ; and particular attention is paid to their food. 



I am also rather astonished to find that Hylolates lioolock [the 

 Gribbon] has a decided partiality for living birds, eating small 

 living birds with avidity in the same way that Nycticebus tardi- 

 gradus [the Slow Loria] does, seizing the bird by the body and 

 always commencing at the head. 



But I could dilate to the extent of some pages on the food and 

 habits of Monkeys. 



Further Remarks on the Lemming. 

 By W. DuppA Crotch, Esq., F.L.S. 



[Eead November 2, 1876.] 

 (Plate XIII.) 



There are three questions in the natural history of the Lemming 

 which still require elucidation, viz. : — 1. Whence do they come? 

 2. "Whither do they go ? and 3. Why do they migrate at all ? 

 With regard to the first of these, no one has yet supplied an answer. 

 They certainly do not exist in my neighbourhood, which is the 

 most elevated region in Scandinavia, during the intervals of mi- 

 gration ; and I suspect that the Kjolen range is assigned to them 

 merely because it is a comparatively unknown district. The answer 

 to question No. 2 is certain : they go to the sea ; those on the east 

 of the backbone of Norway go to the Gulf of Bothnia, and those 

 on the west to the Atlantic Ocean. The question as to the cause 

 of these migrations remains ; and to this, one of three answers has 

 usually been given: — first, an unusual reproduction and conse- 

 quent deficiency of food in their usual quarters ; secondly, the 

 foreknowledge of approaching severe weather, which is a very 

 popular belief in Norway ; thirdly, a natural tendency to de- 

 scend the mountain-slopes both eastwards and westwards from 

 the watershed between Sweden and Norway. 



Now with regard to the first theory, I have invariably noticed 

 during three migrations which I have witnessed, that, just as with 

 the Swallows, one or two individuals have preceded the main body 



lilNN. JOUim. — ZOOLOGY, TOL. XIII. 14 



