442 Miscellaneous. 



companions, which latter journeyed northward, following the course 

 of the retirement of the main ice-sheet. They had found in eleva- 

 tion their congenial climate ; and they have followed this gradually 

 to the top of the mountain, which they have now attained and from 

 which they cannot now retreat. Far off in Labrador the descendants 

 of their ancestral companions fly over wide stretches of country, 

 while they appear to be in prison on the top of a mountain. I conceive 

 that in this way the mountains may generally have secured their 

 alpine animals. The Glacial period cannot strictly be said to have 

 expired ; it exists even now for high levels above the sea, while the 

 Esquimaux finds it yet enduring in the far north. Had other con- 

 ditions been favourable, we might now find Arctic man living on 

 snow-capped mountains within the temperate zone. 



At a height of from 5G00 to G200 feet above the level of the sea, 

 and a mean temperature of about 48 degrees during a short summer, 

 the White-Mountain butterflies (ffineis semidea) yet enjoy a climate 

 like that of Labrador within the limits of New Hampshire. And in 

 the case of moths an analogous state of things exists. The species 

 Anarta melanopa is found on Mount Washington, the Rocky Moun- 

 tains, and Labrador. Agrotis islandica is found in Iceland, Labra- 

 dor, the White Mountains, and perhaps in Colorado. As on islands 

 in the air these insects have been left by the retiring ice-flood 

 during the opening of the Quaternary. 



On inferior elevations (as on Mount Katahdin, in Maine), where 

 we now find no (Eneis butterflies, these may formerly have existed, 

 succumbing to a climate gradually increasing in warmth from which 

 they had no escape ; while the original colonization, in the several 

 instances, must have always greatly depended upon local topography. 



I have briefly endeavoured to show that the present distribution 

 of certain insects may have been brought about by the phenomena 

 attendant on the Glacial period. The discussion of matters con- 

 nected with this theoretical period of the earth's history thus brings 

 out more and more clearly, as it now appears, the fact of its 

 actuality, I hope that my present statements may draw the atten- 

 tion of our zoologists more to the matter, seeing that we have in our 

 own country fields for its full exploration. — Sillhnan's American 

 Jounud, Nov. 1875. 



On the Reprodution of the Eels. By M. C. Dareste. 



Last year M,* Syrski considerably advanced the question of the 

 reproduction of the eels, by showing that in certain eels there exist 

 in the place of the female reproductive organs, some organs of quite 

 different form and structure. M. Syrski regards these as male re- 

 productive organs. The description which he gives of their form 

 and structure renders his opinion very probable. It must, however, 

 be added that M. Syrski could not ascertain the existence of sperma- 

 tozoids in these organs, the proof of which alone could serve to 

 demonstrate certainly their true nature. 



