1869.] 



BOTANY AND ZOOLOGY. 



357 



same deposits of the Valley of Mexico, and referable to a third 

 species of Uquus, viz., Equus tau, Ow. Finally the author 

 proceeds to the description of some fossil upper molar teeth from 

 Pampas deposit, in the bed of a brook falling into the " Arroyo 

 Negro' near Paysandi, Monte Video, showing characters more 

 decisively distinct from any other known species of Equus than 

 have hitherto been described. 



" The degree of curvature of the upper molar teeth exceeds 

 that in Equus curvidens, and equals that in Toxodon ; and the 

 specific name " arcidens " is accordingly proposed for this abori- 

 ginal American species of Horse. It is compared with so much 

 of the characters as have been given by Dr. Lund of his Equus 

 neogceus and E. principalis from Brazilian caverns ; and the dif- 

 ferences from all other Equines which these species and the E. 

 arcidens agree in presenting lead the author to view them as hav- 

 ing, like the Hippotherium of Kaup, formed a generic group in 

 the EquidcE, for which he proposes the name Hippidion. 



The fossil teeth of H. arcidens were found associated with re- 

 mains of Megatlierium and Glyptodon in the above-named local- 

 ity ; the specimens were transmitted and preseuted to the British 

 Museum (in 1867) by the Hon W. G. Lettsom, Her Britannic 

 Majesty's Minister at Monte Video. 



BOTANY AND ZOOLOGY. 



Plants new to Canada. — Mr. Macoun, of Belleville, a 

 corresponding member of the Society, in a letter to one of 

 the Editors, gives a list of the species whii-h he collected, 

 for the first time, during the summer of 1868. The following 

 are some of the more interesting: — 



Cakile Americana Nuttall, 

 Myriophyllum tenellum Bigelow, 

 Aster azureus Lindley, 

 Lobelia Dortmanna Linn. 

 Littorella lacustris Linn. 

 Utricularia cornuta Michx. 



Physalis grandiflora Hooker, 

 Limnanthemum lacunosum Griseb. 

 Polygonum ramossissimum Michx. 

 Potamogeton natans Linn. 



Oakesianus RobbitiSj 



Claytonii Tuckerma7i, 



