416 



usually, homogeneous aspect, which becomes altered during contrac- 

 tion by the supervention of highly refracting transverse ribs, which 

 grow thicker and more approximated as the process advances. 

 Meanwhile the " rod-shaped" nucleus appears to bo pinched up by 

 the contracting fibre, till it assumes a slightly oval form, with the 

 longer diameter transversely placed. 



The author further remarks, that these properties of the constituent 

 elements of involuntary muscular fibre explain in a very beautiful 

 manner the extraordinary range of contractility which characterises 

 the hollow viscera. 



The following Donations to the Library were announced : — 



Collection of Charts, published at the Hydrographic Office, London, 

 with relative Descriptions. — From the Admiralty. 



Results of Meteorological Observations, made at Sundry Academies 

 in the State of New York, from 1826 to 1850 inclusive. Com- 

 piled by F. B. Hough, M.D. 4to. — From the State of New 

 York. 



List of Members and Report of Council, &c., of the Royal Institute 

 of British Architects, 1856. 4to. — From the Institute. 



Annual Report of the Trustees of the New York State Library, 

 1856. 8vo. From the State of Neyj York. 



List of Foreign Correspondents of the Smithsonian Institution, 

 1856. 8vo. — From the Institution. 



Map of Boundary between the United States and Mexico. By W. 

 H. Emory, U.S. Commissioner. — From the Smithsonian Insti- 

 tution. 



Smithsonian Contributions to Knowledge. Vol. VIII. 4to. — 

 From the Institution. 



Nova Acta Academies C^esarese Leopoldino-Carolinse Naturae 

 Curiosorum. Vol. XXV., Pars 2. 4to. — From the Academy. 



Mean Zenith Distances. Collection of all the Results of Observa- 

 tion of each star at Heerelogements-Berg, and Deduction of 

 Mean Zenith Distance, 1843. January 0. — From, the Royal 

 Observatory^ Cape of Good Hope. 



Memoirs of the Royal Astronomical Society. Vol. XXIV. 4to. 

 — From the Society. 



Astronomical and Magnetical, and Meteorological Observations made 



