Fourth Annual Report of the Regents of the Smithsonian Institution to 

 the Senate and House of Representatives, showing the operations, 

 expenditures and condition of the Institution during the year 1849. 

 Washinoton, 1850. 8vo. — From the Smithsonian Institution. 



The Boston Journal of Natural History, containing Papers and Com- 

 munications read before the Boston Society of Natural History, 

 and published by their direction. Vol. VI. No. 2. Boston, 1850. 

 8vo. — From the Boston Society of Natural History. 



The African Repository. Vol. XXVII. No. 1. January, 1851. 

 Washington. 8vo. — From the American Colonization Society. 



Historia de Mejico, desde los primeros movimientos que preparai'on 

 su Independencia en el ano de 1808, hasta la epoca presente. 

 Por Don Lucas Alaman. Tomo II. Mejico, 1850. 8vo. — From 

 the Author. 



Letter to the Rev. John Bachman, D.D. on the question of Hybridity 

 in Animals, considered in reference to the Unity of the Human 

 Species. By Samuel George Morton, M. D. Philadelphia and 

 Edinburgh. Charleston, 1850. 8vo. — From the Author. 



Additional Observations on Hybridity in Animals, and on some col- 

 lateral subjects; being a Reply to the Objections of the Rev. John 

 Bachman, D.D. By Samuel George Morton, M.D. Charleston, 



1850. 8vo. — From the same. 



Contributions to Conchology, No. 8. By Prof. C. B. Adams, of Am- 

 herst College, Mass. New York, 1851. 8vo. — From the Au- 

 thor. 



The American Journal of the Medical Sciences. Edited by Isaac 

 Hays, M.D. New Series. No. 41. January, 1851. Philadel- 

 phia. 8vo. — From the Editor. 



The Medical News and Library. Vol, IX. No. 97. January, 1851. 

 Philadelphia. 8vo. — From Lea <S^ Blanchard. 



The Plough, the Loom and the Anvil. Vol. III. No. 7. January, 



1851. Philadelphia. 8vo. — From J. S. Skinner, Esq. Editor. 

 Journal of the Franklin Institute. Third Series. Vol. XXI. No. 1. 



January, 1851. Philadelphia. 8vo. — From the Institute. 



The Committee, to whom was referred the memoir of Mr. 

 M. Fisher Longstreth, presented at the last meeting, reported 

 in favour of its publication in the Transactions of the Society, 

 which was ordered accordingly. 



The Committee, to whom was referred the communication 

 of Dr. Leidy, presented at the last meeting, reported in favour 



