f>S (May, 



May 9th, 1848. 

 Vice President Morton in the Chair. 



Dr. Pickering called the attention of the Society to the fact that in 

 all the estimates relating to the length of the year, no reference had 

 been made to the time taken for light to reach us from the sun, about 

 eight minutes and a half. He supposed that if that estimate was 

 taken into the calculations, a slight difference would be found in the 

 results. 



Dr. Bridges remarked that the same estimate was taken at the com- 

 mencement of the calculation as at the end — that the relative position 

 of the sun to the earth was the same at both times; and he asked if 

 the consequence was not, that the length of time between each posi- 

 tion so estimated would be precisely the same as if the allowance 

 spoken of by Dr. Pickering wa^ made ? 



The effect of making such allowance would only be to add eight 

 minutes and a half to each end, which would, of course, leave the 

 difference between such ends the same as before. 



Dr. Meigs offered some remarks on the mode of copulation in the 

 Opossum, which he felt satisfied was performed mo)-e canino, as ob- 

 served by Dr. Ellerslie Wallace of this city; and that the statements 

 contained in a recent communication to the Academy on this subject, 

 by Drs, Bachman and Michel, that the connection took place in a 

 lateral position, were erroneous. 



May 16th, 1848. 

 Dr. Bridges in the Chair. 



Dr. Gambel presented and read a communication from Major McCall, 

 entitled " Some Notes on Mexican Birds heretofore not fully described ;" 

 which was referred to a Committee consisting of Dr. Gambel, Mr. 

 Harris, and Dr. Wilson. 



May 23, 1848. 



Mr. Vaux in the Chair. 



Dr. Bridges presented a paper by T. A. Conrad, being "Additions" 

 to his " Observations on the Eocene formation and descriptions of one 

 hundred and five new fossils of that period, from the vicinity of 

 Vicksburg, Mississippi, with an appendix," read on the 12th October, 

 1847, intended to be embodied with that communication, and for pub- 

 lication in the Journal. 



Referred to the former Committee, Dr. Griffith being substituted for 

 Dr. Leid}^, absent. 



