204 Linnenn Society. [Nov. 16, 



observations to which they have subsequently led on the part of 

 others ; which appear to necessitate important changes in our gene- 

 ral views of the reproduction of plants. He finds, however, that the 

 results of some of these later observations differ in many respects 

 not only from those of Suminski, but also among themselves ; and 

 that opinions are divided both as to the actuality of the most im- 

 portant fact of all, viz. the process of impregnation, and as to the 

 period and circumstances of its occurrence. Under these circum- 

 tances he has thought he would be performing a useful task in sub- 

 jecting the question to minute investigation, in the course of which 

 he has carefully traced the development entirely through its course 

 from the spore to the young leafy plant, applying every available 

 means to clear up the anatomical conditions in each stage of the 

 progress. The drawings which accompany the memoir were nearly 

 all made by means of the camera lucida eye-piece, so that they repre- 

 sent preparations actually seen. 



The subject is treated of under three heads ; the first section con- 

 taining the author's own observations ; the second, a critical exami- 

 nation of those of preceding authors ; and the third, a few remarks 

 on the general bearing of the results upon vegetable physiology. 



Under the first head, Mr. Henfrey describes first the prothalliura, 

 and its mode of growth, enlargement and decay ; secondly, the 

 antheridia, with their sperm-cells and spermatozoids ; thirdly, the 

 archegonia, with their papillae and embryo- sacs ; and fourthly, he 

 gives his own view of the development of the embryo. On all these 

 points he enters into much detail, tracing the several stages of the 

 process with great minuteness. In his criticism of previous obser- 

 vations, he passes in review the facts and opinions stated by Nageli, 

 Suminski, Wigand, Thuret, Hofmeister, Schacht, Mettenius, Von 

 Mercklin, and Hofmeister again ; and indicates the points in which 

 they severally diifer from each other, and also those in which he 

 himself either coincides with or diff'ers from each of them. The 

 memoir is so completely one of detail, that under these two principal 

 divisions it would be difficult to give a sufficiently clear abstract 

 without running to too great a length ; and this is the less necessary 

 as the memoir itself will immediately appear in full in the Society's 

 ' Transactions.' 



Under the head of " Development of the embryo " the author 

 gives the following statement of his opinion on the question of 

 impregnation, and the mode in which it is eff"ected : — " My opinion 

 with regard to the fertilization is, that the operation is eff^ected 

 by the contact of one or more spermatozoids with the mucilaginous 



