103 



by Dr. H. as belonging to the young of the M. giganteum. See 

 Transactions, Vol. IV., N. S., PI. XX. In the latter specimen the 

 alveolus was so small and imperfect, and so different from that in the 

 species of Tetracaulodon then known, that Dr. II. considered it an 

 accidental formation. In the specimen in Mr. Koch's collection the 

 alveolus is sufficiently perfect, the lining plate of bone in part remain- 

 ing, to place beyond all doubt its being a socket for a tusk. 



Two of the fragments of upper jaws are extremely interesting, from 

 possessing, one an entire tusk, and the other the inner portion of both 

 tusks, apparently in their original position ; thus solving the problem 

 as to the position of the tusks in this genus, and showing it to be the 

 same as in the elephant. 



The collection of bones forming the skeleton, called by Mr. Koch 

 the Missourium, though very unnaturally put together, is an object of 

 interest, from the large size and fine state of preservation of some of 

 the bones, particularly the femur and the atlas. The head is far less 

 perfect than the one belonging to the Society. The whole vault of the 

 cranium, except the inner table, is wanting. The two tables of the 

 cranium being widely separated in this genus, the absence of the outer 

 table and the diploe gives to the head a remarkably flat appearance. 

 This, with the smoothness of a great part of the upper surface, result- 

 ing from the natural structure of the cells of the diploe, which are 

 very large, led Mr. Koch to believe that the cranium was entire, and 

 that it belonged to an animal different from the Mastodon. 



Professor Bache presented some further astronomical obser- 

 vations from Mr. Riimker, of Hamburg. 



These observations are published in the Astronomische Nachrich- 

 ten, No. 432, which has been received in this country since the meet- 

 ing of the Society. 



Stated Meeting, October 15. 



Present, thirty-seven members. 



Judge Hofkinson, Vice President, in the Chair. 



Letters were received and read — 



From the Royal Society of Sciences of Copenhagen, dated 



N 



