1878. | The Microscope in the Examination of Rocks. 13 
mals are very much alike, being frequently started under an old 
log and continuing under the same for its entire length. 
They do not hibernate, but keep their burrows open all winter; 
beaten trails in the snow are often seen, leading above ground for 
a few feet, from one hole to another. They are able to gather 
their food at any time of the year, seldom going more than a few 
feet from the entrance of their holes to procure it. . 
I have never heard them make any kind of noise by day or 
night, save a kind of growl when caught in a trap. They are 
easily caught in steel traps, to the contrary of what many with 
whom I have conversed assert. I have caught numbers of them 
without even covering the traps. The No. o “Newhouse” trap 
is the one I have used. They are quite strong, and generally 
break their legs ; and, if long in the trap, will be found dead. 
A friend of mine had one domesticated for several months. It — 
readily ate apples and other fruit, vegetables, etc., and seemed to 
bear confinement very well. It took great pleasure in paddling 
in a dish of water; slept most of the time during the day, but 
awakened to activity as night came on. Another man caught one. 
while young, and let it run about the house. As it grew larger 
it dug a hole in the ground near the well, where it lived con- 
tentedly for a long time, when a strange dog killed it. 
My knowledge respecting the breeding of the show’tl is limited 
and uncertain. People living in the vicinity of these animals tell 
me that the young show’tls just weaned make their appearance 
during the month of June, in numbers from three to five ata 
birth. The females have six teats. From my present knowl- 
edge of them I suspect they breed but once a year, like the beaver.* 
See 
THE MICROSCOPE AS A MEANS OF EXAMINATION 
OF ROCKS AND FOSSILS. 
BY DR. R. FRITZ-GAERTNER. 
=e E examination of rocks in regard to their lithological char- 
acter is accompanied with great difficulties whenever their com- 
posing minerals are so minute and so thoroughly intermingled 
* On the habits of this animal compare also: Coues, Monograph of Rodentia of 
North America, 1877, pp. 590-598; Matteson, Am. Nat. XI, 1877, pp. 434, 435; 
uty, London Field for May 5, 1877.—E. C. 
