[ 108 ] 14 



terized under the names of Eutcrobryus Eles^ans, E. aiienuatus, Arthro- 

 mitus cristatus, Cladophytum comaium and Corynocladus radiotus. 



The mode of growth and reproduction of several of the species has been 

 carefully traced and fully illustrated by figures. 



The researches are prefaced by some observations on the laws of para- 

 sitic life in general, which are presented in a highly philosophical manner, 

 and entirely free from- hypothesis — the whole forming one of the most 

 remarkable papers on physiology which has ever been produced by our 

 countrymen. 



Lieutenant Charles Henry Davis, United States Navy, Superintendent of 

 the American Nautical Almanac, has presented a memoir on the dynamic 

 effects of the tides. 



This memoir is a continuation of one presented by the author to the 

 American Academy a few years ago, and is of much interest, not only in a 

 scientific point of view, as connected with important geological changes, 

 but also on account of the practical bearings upon the transformations 

 which are constantly going on at the entrance of rivers, channels, and 

 in the formation of headlands and promontories. Were our globe a 

 perfect spheroid of revolution, surrounded by water of uniform depth, 

 the tides of the ocean would consist of nearly perpendicular undulations 

 of the particles of the liquid, and a mere translation of form, without a 

 transference of matter. But, in the case of a globe of irregular surface, 

 covered with water of varying depth, the oscillations of the ocean must 

 constantly produce currents in definite directions which tend continually 

 to change the position of the movable materials which are found at the 

 bottom of the sea, particularly as we approach land. A part of the force 

 of the particles of water forming the sinking swell of the wave, in the case 

 of an obstruction to their free descent by a diminished depth, is expended 

 in producing a current along the inclined plane of the surface leading to . 

 the shore. 



Lieutenant Davis has entered with much ardor upon the new field of 

 research, and after an examination of various parts of the shore of the 

 United States, through a series of years, in which he was engaged on the 

 coast survey, has succeeded in developing tne laws of action which give 

 rise to the changes before mentioned. 



He finds that the tendency of the flood-tine is to transport the matter 

 from the bottom of the ocean and deposit it on land. He is enabled to 

 explain the character of the alluvial formations, to account for their pecu- 

 liar shape, their comparative sizes, their accumulation, and to predict the 

 results of certain combinations of circumstances on their future changes. 

 The particular object of this memoir is to inquire into the mechanical ope- 

 rations of the tides, and the uses they may have served in the general 

 economy of the glolie in directing the loose materials of the earth's crust. 



Smithsonian reports and other pxihlications. — Since the last meeting of 

 the Board of Regents, the report of Professor Jewett on the public libraries 

 of the United States has been published and widely distributed. It is im- 

 possible to collect at once full and reliable accounts of all the libraries of 

 the country, and this report is intended merely as a beginning, to be fol- 

 lowed by others on the same subject. It has been sent to all the libraries 

 of the United States, with the request that its deficiencies may be pointed 

 out and additional materials furnished to rerwler it more perfect. The 

 great interest which is felt in this work is manifested by the amount of sta- 



