TEANSACTIONS OF THE SECTIONS. 87 



notes into a fit state for publication, but in February I forwarded a paper to the 

 Linnean Societj' of London, which was read on the 4th of March, in which the 

 new discovery was fully illustrated and explained, as observed in the ovules of San- 

 talum album. That memoir contained many details respecting the development of 

 the ovule in all its stages ; but the point of greatest physiological importance, and of 

 absolute novelt)', was the demonstration, that previously to the period when the 

 pollen-tube reaches the embryo-sac, the germinal vesicles, or rather "corpuscles," 

 are not perfect cells in the old and ordinary acceptation of the term in vegetable 

 anatomy, but are merely definitely-bounded, spherical or ellipsoidal masses of gra- 

 nular protoplusm ; being, in fact, in the same condition as the zoospores of the Con- 

 fervoid Algae, before they are discharged from the parent-cell in swarming. The 

 pollen-tube reaches the summit of the erabryo-sac, and adheres very firmly to it. 

 It was not decided whether the membranes gave way, so as to allow the contents 

 of the pollen-tube to be discharged into the embryo-sac, but this appeared probable. 

 The result of the application of the pollen-tube to the end of the erabryo-sac above 

 the germinal corpuscles, was very quickly evident in the appearance of a solid cellu- 

 lose membrane as a new coat to that germinal corpuscle which was to give origin to 

 the embryo, converting it into a perfect cell. This cell then became divided into 

 two by a transverse septum, the upper half forming the " suspensor"-cel!, while 

 the lower increased in size, and by cell-division became a cellular mass, ultimately 

 taking the proper form of the embryo. 



Botanists who are acquainted with the recent discoveries of Thuret, Pringsheim, 

 Cohn and others in the reproduction of the Algse, will see the interesting connexion 

 which exists between the process above described, and the phaenomena of fecunda- 

 tion of the species of the lower plants. I have dwelt upon this in the memoir 

 presented to the Linnean Society, and stated my opinion, since confirmed by further 

 observation, that the germinal corpuscle of the archegonium of the Ferns is likewise 

 destitute of a cellulose coat until it is fertilized by the contact of the spermatozoids. 



I send with this notice some drawings illustrating the phaenomena presented in 

 the fertilization of the ovule of Santalum. 



Having arrived at the above views, it was with great pleasure I last week received 

 the report of the May sitting of the Berlin Academy, containing a paper by Dr. 

 Schacht, transmitted from Madeira, with the date of April, on the same subject, 

 and confirming my account in all essential respects. His observations on the ovule 

 of Gladiolus segetum have induced him not only to admit the error in his long and 

 warm advocacy of the pollinic hypothesis, but to assert that the germinal corpuscles 

 are, as stated by me, pre-existent as protoplasmic masses destitute of a membrane, 

 and that their conversion into true cells, with a cellulose wall, is the result, and the 

 first evidence of the process of fertilization by the arteries of the pollen-tube. This 

 corroboration of my statements by an independent observer, is very satisfactory, 

 seeing the delicacy of the observations on which they rest; but it may be observed, 

 that the new views form a natural development of those previously entertained by 

 Amici's school, resulting from a more minute attention to the nature of " cell-con- 

 tents" than was formerly paid. It is probable that part of the error of the pollinists, 

 together with Tulasne's inability to find the germinal corpuscles before impregnation, 

 may have arisen from the great liability to destruction of the corpuscles by external 

 agents, and alteration by endosmose. We have observed them best either by moist- 

 ening the fresh preparations with solution of sugar instead of pure water, or by 

 soaking the ovules in spirit before dissection. — August 2, 1856. 



On the Triiicoidal Forms q/"iEgilops and on the Specific Identity of Centaurea 

 nigra and C. nigrescens. By the Rev. Professor Henslow, M.A., F.R.S. 

 In this paper the Professor recorded the result of his own experiments, in which 

 he had so far succeeded in changing the character of jEgilops squarrosa as to lead 

 him to conclude that M. Fabre's original statement, that ^. ovata was the origin 

 of the domestic wheat, Triticum sativum, was not altogether without foundation. 

 He exhibited specimens in which the form of jEgilops squarrosa had undergone 

 considerable change ; but he had not succeeded in obtaining the characters of Triti- 



