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 

 cracking nuts or hard-shelled seeds, although evidently also used for 

 grinding. 



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. Mies. La Plata, vol. ix. p. 407. 



American Plant-Notes. 



Recent numbers of Rhodora, 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 



