1872.] 



SENATE— No. 249. 



13 



From the Hocky Mountain Expedition. 

 Fifteen hundred skins, 200 species; 100 specimens in alcohol, 

 30 species ; 33 nests and 160 egors, 20 species; several lots of young 

 birds in alcohol, and a number of skulls. 



By Purchase. 



Forty-three skins, 21 species; 34 specimens in alcohol, 15 

 species, from Dallas, Texas; 74 skins, 7 species, from Massachu- 

 setts; 1,430 skins, about 100 species, chiefly from Florida. 



Report of Dr. G. A. Maack. 

 At the close of my last report, November, 1870, 1 expressed 

 the hope that it might be possible for me, iu the position of 

 Geologist and Naturalist of the U. S. Darien Exploring Expedi- 

 tion, to which I was appointed at that time, to do, besides my 

 official work for the United States Government, some good work 

 for our Museum. At present, when everything I have collected 

 has arrived at Cambridge in good condition, I am happy to be 

 able to report that my hope has been wholly fulfilled. Thirty 

 cases filled with geological, palaeontological and lithological 

 specimens from the Isthmus of Panama, Darien and Choc6, col- 

 lected on the Atlantic side as well as on the Pacific, have been 

 the result for our Museum, as the Hon. Secretary of State has 

 given permission to unite all the collections with those of the 

 Museum. 



It may be allowed to me to return here publicly our heartiest 

 thanks to the Hon. Secretary of the Navy for this contribution 

 to our collections. 



In giving some outlines of them, I may say, first, that I labelled 

 all the various specimens with the greatest care, to be sure of 

 what occurs on the Atlantic slope and what on the Pacific slope. 

 This careful labelling is nowhere so necessary as on the Isthmus, 

 where the continental mass of Central America contracts to its 

 greatest narrowness, and where the influence of the climatic 

 differences between the two ocean-shores, as well as that of the 

 different geological and botanical characters of this region upon 

 the development of animal life, can be studied better than at 

 any other place, after having ascertained carefully the habitat of 

 the species. 



