74 



times been asserted against the Spermatozoa or spermatic cor- 

 puscules, are again brought forward ; they are said to be fecula 

 or drops of oil, in which view 1 do not concur ;. I have, how- 

 ever, already stated my opinion on this subject in last year's 

 report. Starch occurs only in imperfectly formed pollinic 

 vesicles ; not rarely in Coniferce and in some water plants. I 

 have also been able to observe in Muscari moschatum that in 

 such imperfectly developed pollinic vesicles the masses of fe- 

 cula which occur in them are converted into a gummy sub- 

 stance arid decompose into small molecules which have a very 

 lively motion, resembling in every respect the phenomenon de- 

 scribed by me in the cells of Marchantia polymorpha *. In 

 some cells of this plant there occur instead of the common 

 green cellular sap globules some large balls of a yellowish 

 brown substance, which have been already observed and fi- 

 gured by Mirbel. I followed up the formation of these masses 

 from the globules of starch, which deliquesce and are then 

 converted into a gum. When these globules are perfectly 

 developed and of a yellowish brown colour, they decompose 

 on the smallest touch into innumerable minute brownish mo- 

 lecules, which for days exhibit the most lively motions,, having 

 an appearance similar to the motions in solutions of indigo, 

 gum-arabic, &c., only somewhat more active. 



The second section treats of the coats of the pollen. A sim- 

 ple membrane and one of a more compound structure are to 

 be distinguished on the pollinic vesicles. Some plants exhibit 

 but one tunic, others on the contrary three and even four. 

 Most frequently but two tunics occur, and they are termed 

 the inner and the outer coat; but where a duplication of one 

 or both these membranes exists these names do not suffice, 

 and on that account he proposes for the entire series of mem- 

 branes, when they are all four present, the terms Intine, Ex- 

 intine, Intexine, and Exine, which however cannot be admitted, 

 for the fact is quite different to what M. Fritzsche supposes f. 



The inner tunic is from its simplicity easily distinguished 

 from the outer membrane, and chemical agents afford ample 

 means for separating them. Concentrated sulphuric acid de- 

 stroys the inner membrane, but the outer one with its ap- 



* Wiegmann's Archiv, 1837, part iii. p. 428. 



[f Similar views are however entertained by H. Giratid. See his paper 

 in the Annals of Natural History, vol. ii. p. 399. W. F.] 



