844 Proceedings of the British Association. 



of the Mustelfie is limited southwards to the northern or middle 

 districts of the United States. Whether any of the American and 

 European species of this genus he really identical, is involved in 

 great uncertainty. Of the three Otters of North America, one ap- 

 pears to be identical with that of Europe ; and another, if correctly 

 identified as the Lutra Brasiliensisy has a most extensive range, 

 from the Arctic Sea through great part of South America. Eight 

 species of the genus Canis are found in North America ; but there 

 is great difficulty in distinguishing the species, and in identifying 

 them with any of those of Europe. The domestic dog breeds with 

 the wolf and fox, and their offspring is prolific. Eight species of 

 the genus Felis were mentioned by Dr Richardson, three of which 

 extend from South America into the south-western territories of 

 the United States ; and some of the others are still doubtful as 

 North American species. The nine species of Amphibia found in 

 North America, are mostly common to the northern seas of the 

 Old and New Worlds : the genus Otaria alone being confined to 

 the North Pacific ; and even these range to the Asiatic coast. The 

 specific identity of some of the seals is involved in very great 

 doubt. In the order Rodentia, there have been between seventy 

 and eighty species discovered ; and here North America surpasses 

 every quarter of the globe in the abundance and variety of form 

 which these animals assume. The squirrels are not yet satisfactorily 

 determined. The marmots are numerous, except in the subgenus 

 Spermophilus. There is only one which may possibly be common 

 to the New and Old World. There is only one of the restricted 

 genus Mus, which is unequivocally indigenous to North America ; 

 and this closely resembles the European M. sylvestris. Other spe- 

 cies have been introduced from the opposite side of the Atlantic. 



Mr Bowman read a communication respecting the Longevity of 

 the Yew-Tree ; and mentioned the result of his observations upon 

 the growth of several young trees, by which it appeared that their 

 diameters increased during the first 120 years, at the rate of at least 

 2 lines, or the one- sixth of an inch per annum; and that under fa- 

 vourable circumstances the growth was still more rapid. In the 

 church-yard at^Gresford, near Wrexham, North Wales, are eighteen 

 yew-trees, which are stated by the parish register for 1726 to have 

 been planted in that year. The average of the diameters of these 

 trees is 20 inches. Mr Bowman then remarked on two yew-trees 

 of large dimensions, from the trunks of which he had obtained sec- 

 tions. One is in the same churchyard as those above mentioned, 



