the number of 1,000 on a single leaf: each gall inserted in a deep cavity 

 which causes, on the upper surface, a bulging of a straw-yellow color, 

 irregularly sub-conical, with the top flattened, or concave, and with a mi- 

 nute central nipple, sometimes obsolete : the galls becoming detached and 

 falling to the ground in autumn, leaving a pale, fulvous, circular disc at 

 the bottom of the cavity. The gall has an average diameter of i mm., and 

 the color and general appearance of a miniature acorn — the base being 

 paler than the sides and conically produced to the central point of attach- 

 ment. The apical portion is slightly constricted into a deep purple-brown 

 rim, and the top within this rim is flat, with a small central nipple. 



Received at different times from M. W. Harrington, of Ann Arbor, 

 Mich. ; from Irvin Armstrong, of Vevay, Ind. ; from N. B. Baldwin, of 

 Elgin, Ills., and from Wm. R. Howard, of Forsyth, Mo. : also sufficiently 

 common in St. Louis Countv. 



December 20, 1875. 

 W. T. Harris, President, in the chair. 



Twelve members present — J. M. Mansfield, Professor of Natu- 

 ral Philosophy, Mt. Pleasant, Iowa, assisting. 



The Corresponding Secretary laid a large number of exchanges 

 on the table, among them the transactions of Academies in Na- 

 ples, Milan, Bologna, Florence, and Rome. 



In reply to a letter from Thos. Bicknell, editor of the New 

 England Journal, asking for a report of the proceedings of the 

 Academy for publication in the Journal, Mr. Riley suggested 

 the propriety of making arrangements with one of the daily pa- 

 pers to publish a full and authentic account of our proceedings. 

 There was an increasing demand for scientific information in the 

 country, and such an arrangement would prove advantageous 

 both to the paper and to the Academy. — On motion of Judge 

 Holmes, Mr. Riley was appointed a Committee of one to see to 

 the matter. 



A couple of molar teeth, apparently of Mastodon angusti- 

 dens, were exhibited by Mr. Todd. He said they had been found 

 in Pike County of this State, and brought to the city by Mr. Jame- 

 son, of Louisiana, Mo. They had been taken from a creek that 

 entered the Mississippi River at the upper end of Clarksville, and 

 were very well preserved, having the enamel still on them. A por- 

 tion of the mastodon's jaw was attached to one of them. — Judge 

 Holmes remarked that such remains were most frequently found 

 in the Loess or Bluff formation of the Mississippi Valley, often 

 in quite superficial deposits, and in the beds of ancient lakes or 

 swamps in the eastern parts of the United States. Dr. Koch had 



