404 [October, 



October 18th. 

 Yice-President Bridges in the Chair. 



A letter was read from the Historical Society of Pennsylvania, dated 

 October 7th, 1853, acknowledging the receipt of Proceedings, and also 

 presenting the volumes of their Memoirs announced this evening. 



Also a letter from Philo R. Hoy, M. D., dated Racine, Wisconsin, 

 October 7th, 1853, acknowledging the receipt of his notice of election as 

 a Correspondent. 



Major Le Conte presented a paper for publication, entitled *' Obser- 

 vations on Crotalus durissusand C. adamanteus, of Authors," which was 

 referred to Dr. Hallowell, Professor Haldeman and Dr. Leidy. 



Mr. C. Grirard presented a paper for publication, entitled "Descriptions 

 of new species of Reptiles collected by the U. S. Exploring Expedition, 

 under Captain Wilkes part 2nd." Referred to Dr. Hallowell, Dr. Le 

 Conte and Dr. Leidy. 



A continuation of Dr. Hoy's " Notes on the Ornithology of Wiscon- 

 sin," was presented by Mr. Cassin, and referred to the Committee on 

 the previous portions of the paper. 



Dr. Leidy called the attention of the Society to the fragment of a jaw 

 of an extinct Saurian animal, discovered by Mr. M'Leod in the New 

 Red Sandstone of Prince Edward's Island. The specimen indicates a 

 new and remarkable genus, for which Dr. Leidy proposed the name 

 Bathygnathus borealis. 



The portion of the jaw is the anterior part of the right lower half, and 

 measures five inches in depth. It contains eight teeth, of which the long- 

 est when perfect has been two inches. They are compressed conoidal and 

 curved, with the borders finely serrulated. 



Professor Haldeman proposed to change the pre-occupied name of his 

 Meloe parvus^ in the report of Captain Stansbury's Expedition, to M. 

 parvulus. 



October 25th. 



Vice-President Bridges in the Chair. 



The Committee on Major Le Conte's descriptions of new Arvicolae, 

 reported in favor of publication. 



Description of three new species of Americati Arvicolce, with remarks upon some 



other American Rodents. 



By John Lk Conte. 



From amongst the smaller mammals of this country I select out the genus 

 Arvicola as a proper subject for a few remarks. Notwithstanding the researches 

 of those who have preceded me, I have, within the last year, detected three 

 species which have not yet been described. The object of my observations is 

 not so much to bring these before the world, as to settle the synonomy of those 

 which are already found in the books. The confusion among them is very great, 

 and apparently every day increasing. What may be the result of my endeavors 

 to enlighten this darkness, it is not for me to say. I can only hope that my con- 



