138 Bibliographical Notices. 



from the circumstance of their flourishing equally either in fresh 

 or in salt water. The fructification of Bangia has hitherto been ob- 

 scure ; it has recently been investigated by Dr. Cohn in ' Schulze's 

 Archiv,' 1867, Band iii. 



In the second family, the Chcoitninsiacece, there is but one genus, 

 Cliantransia. And the third family, the Batracliospermacece, con- 

 tains only tu'o, Batrachospermum and Tliorea. The former genus 

 has lately been the subject of some very interesting observations by 

 Messrs. Bomet and Thuret* and the Comte de Solms-Laubachf. 

 These observers have indei>endently arrived at similar conclusions 

 with regard to the mode of reproduction in Batracliospermnm. The 

 details cannot be given here, and, in fact, would be hardly intelli- 

 gible without figures. The observations of Messrs. Bornet and 

 Thuret are not confined to the genus Batracliospenyium, but extend 

 to a multitude of other Floridece, and seem at last to have solved 

 the problem as to the mode of sexual reproduction in that tribe of 

 Algae. 



Hihhnhrandtia is the only freshwater genus in the fourth family, 

 the HUdenhnindtiacece. It has been the subject of some observa- 

 tions by Mr. Carter in Seemann's ' Journal of Botany ' for 1864, 

 p. 225. 



Lemanm, Bory, a singular genus, beautifidly figured by Kiitzing 

 in his ' Phycologia Generalis' (pi. 19), and Compsopoijon of Mon- 

 tague, represented in Europe by a single species, Compsopogon Cori- 

 ncddii, Jitz. (Lemanea C'orinaldii of Meueghini), compose the fifth 

 and last family, the Lemaneacece, with which the work closes. 



It is hoped that enoiigh has been said to give a sufficient idea of the 

 nature of Dr. Rabcnhorst's work, and to show the important assistance 

 it will render to all who are engaged in the study of freshwater Algse. 

 The difficulty of making any entirely satisfactory classification of 

 plants so little resembling one another as the different tribes of 

 Alga3 is very great. In judging of any arrangement, it will always 

 be necessary to bear in mind that (as Messrs. Bornet and Thuret 

 have remarked) the name " Algse" does not represent " un ensem- 

 ble nettement limite," that it is, in reality, only a common name 

 under which are comprised families belonging to different types, and 

 which have often no other affinities than the absence of vascular 

 tissue and the medium in which they grow. 



With these remarks, we can cordially recommend the work before 

 us as an indispensable addition to the libraries of all algologists. 



Microscopic Objects figured and described. By John H. Martik, 

 Secretary to the Maidstone and Mid-Kent Natural-History Society. 

 No. I. London : John Van Voorst. 



We welcome with much satisfaction the appearance of this unpre- 

 tending but most useful collection of drawings illustrative of the 

 microscopic appearances presented by an extensive and well-selected 



* Ann. d. So. Nat. s6r. 5. vol. vii. p. 144. 

 t Bot. Zeit. May 1867, nos. 21 and 22. 



