94 REVIEWS. 



selves to it by the ciliated end, apparently by one of the 

 cilia, and at length come to rest in contact with it ; but he 

 could not detect any material penetration of them into the 

 body of the spore. Pringsheim, confirming all Thuret's ob- 

 servations, thinks also that the spermatozoids actually pene- 

 trate the sperm-mass ; but there is no direct proof of it. 

 Indeed Thuret, in a very recent article (" Annales des Sci- 

 ences Naturelles," 4 ser., vii., 1857), indicates the grounds of 

 Pringsheim's probable mistake. The most interesting point in 

 this last article by Thuret relates to the suddenness with which 

 the cell-membrane is formed on the spore of Fucus after the 

 access of the spermatozoids and the accomplishment of the act 

 of fecundation. In six or eight minutes traces of the forma- 

 tion of the membrane are recognizable upon a considerable 

 number of the spores. In ten minutes the presence of a mem- 

 brane may be clearly made manifest by the application of 

 chloride of zinc. In an hour the membrane has acquired con- 

 siderable firmness and thickness, and the presence of cellulose 

 is revealed by the action of sulphuric acid and iodine; an 

 hour later and the blue coloration under the test is decided. 



In the higher Cryptogamia and in the PTianerogamia, 

 Radlkofer's treatise, though interesting for the history, offers 

 nothing new to our readers. In fact, its date precluded it 

 from containing much of what is referred to in the preced- 

 ing paragraphs. But the subject is still to be continued. 



DR. HOOKER ON THE BALANOPHORE^. 



Although read before the Linnrran Society nearly three 

 years ago, this fine memoir ^ was published only last summer. 

 The delay has probably been owing, in a great part, to the 

 time requisite for the engraving of the very beautiful and 



^ On the Structure and Affinities of Balanophoreae, by J. D. Hooker, (sep- 

 arately issued from the Transactions of the Linncean Society of London, 

 xxii.) London, 1857. (American Journal of Science and Arts, 2 ser., 

 XXV. lie. ) 



