1899] NOTES ON AMERICAN MAMMALS 313 
depth of the ramus from the alveoli to the angle. These tell an un- 
mistakable story ;—unusual capacity for crushing or grinding, and the 
attendant specialisation of the premolar to perform the function laid 
upon it. Just as in the Carnivora, the first lower molar, lying im- 
mediately anterior to the insertion of the masseter muscles, has de- 
veloped into the great shearing tooth; so in these forms the last 
premolar has fitted itself for a crushing implement, which has reached 
the highest degree of specialisation known to Rodentia.” It is then 
suggested that the teeth in question may have been employed for 
eracking nuts or hard-shelled seeds, although evidently also used for 
erinding. 
The 15th part of the “North American Fauna” is devoted to a mono- 
graph of the genus Zapus (jumping-mice), the range of which has 
recently been increased by the discovery of a species in North-West 
China. Mr. E. A. Preble is the author of the memoir in question, and 
appears to have done his work well. 
The naturalists of the La Plata Museum appear convinced that the 
so-called Neomylodon listai—the ground-sloth, whose skin has been 
discovered in a cave in Patagonia—is really inseparable from the genus 
Glossotherium, or Grypotherium, and conclude that it was kept in a 
domestic state by the early inhabitants of Patagonia. They further 
believe it to be now extinct. The first instalment of a conjoint paper 
on the subject is published in the Rev. Mus. La Plata, vol. ix. p. 407. 
American Plant-Notes. 
RECENT numbers of Lhodora, the journal of the New England Botanical 
Club, maintain the reputation of this small but useful periodical. 
Among numerous notes and short papers dealing chiefly with the 
native flora, we note some suggestions on seaweed collecting by F. S. 
Collins, and an account of past and present floral conditions in Central 
Massachusetts by G. E. Stone. The last mentioned traces the effects 
of deforestation on the flora, especially with regard to the proportion 
and nature of the trees. Several species, such as the hemlock, beech, 
and canoe-birch have become less abundant, their places being more or 
less occupied by the quicker growing white birch and poplar. The 
complete and continual removal of forest has also exerted a great 
influence upon many smaller plants, and there is a marked decline in 
the luxuriance of humus-loving orchids, strawberries and meadow- 
grasses. 
The July number of the Plant World contains a picture and short 
account of the liberty tree of Annapolis, an ancient and magnificent 
tulip-tree with numerous and various historic associations. There is 
also a laudatory exposition of ecology, or the study of the relation of 
