THE HIGHER CRYPTOGAMIA. 413 



by two, very rarely three or four, endogenous daughter-cells. 

 In Pinus sylvestris on the other hand very many of the 

 germinal vesicles, and in Pinus Slrobus almost all of them, 

 contain, even before impregnation, several sometimes as 

 many as six, usually four nucleolate daughter-cells. The 

 membranes of the germinal vesicles, as well as those 

 of the daughter-cells formed before their impregnation, 

 dissolve in water. The germinal vesicles of Pinus cana- 

 densis contain small amyloid granules which are not found 

 in other species. The phenomena which may be ob- 

 served in the formation of the germinal vesicles, resemble 

 generally those which appear in the formation of the cells 

 of the endosperm of phsenogams in the restricted sense 

 of the word. The free cell- formation in the impregnated 

 embryo-sac of the Iridese* offers the most points of 

 resemblance. As in that case the first organized forma- 

 tions have the form of vesicles of moderate size. They 

 either possess fluid contents only, or in more rare instances 

 they have one or two spherical bodies (nucleoli) of a 

 strongly refractive substance, floating in the fluid contents. 

 These formations according to current notions must be 

 considered as nuclei. The larger of these vesicles exhibit 

 in their interior a small spherical, cellular formation the 

 nucleus around which the cell originated situated some- 

 what excentrically, and exactly similar to the above-men- 

 tioned freely -floating bodies. There is only one circum- 

 stance which does not entirely accord with these explana- 

 tions of the observations, and that is, that sometimes 

 (although not often), cells are found whose single nucleus 

 is decidedly smaller than any one of the freely-floating 

 nuclei observed contemporaneously in the same corpus- 

 culmn. This may however very probably depend upon 

 individual peculiarities. It may well be, that the moment 

 at which a cell is formed round a nucleus, is determined 

 by circumstances quite unconnected with the fact whether 

 or not the nucleus has attained its greatest size. A 

 nucleus might, long before it was full-grown, become the 

 middle point of a cell in process of formation. If it be 



* Entstelmng des Embryo,' p. 27. 



