412 HOFMKISTER, ON 



size ; in Juniperus (PL LXV, fig. 2) until the full size is 

 attained. In Pinus it usually lies at the upper end of the 

 corpusculum — that end which is turned towards the micro- 

 pyle — rarely at the opposite end ; it is embedded in a muci- 

 laginous layer, which clothes the inner wall of the organ, and 

 which in Pinus is thin, and rendered turbid by numerous 

 granules (PL LXV, figs. 5, 6), and in Juniperus and Cu- 

 pressus* firm and transparent ; in the centre of the corpus- 

 culum there is only a small ellipsoidal cavity filled with 

 watery fluid. At last the nucleus is dissolved ; in Pinus 

 sylvestris this is often preceded by the formation of a free 

 spherical cell around this nucleusf (PL LX, fig. 5). At 

 last it disappears from observation, and at the same time, in 

 the Abietinese, several vacuoles make their appearance : the 

 latter are so numerous and so close together in Pinus sylves- 

 tris and Strobus, that they impart a frothy aspect to the 

 whole contents of the corpusculum ; in Pinus Larix and 

 canadensis they are less numerous and of very unequal 

 size. During the further development of the corpuscula 

 the number of these vacuoles diminishes. Nuclei and free 

 nucleolate spherical cells now appear amongst them, the 

 latter at first being only small and few in number. Their 

 number however soon increases, whilst that of the vacuoles 

 diminishes more and more. In Pinus sylvestris and Strobus, 

 and in Abies Larix, the latter disappear entirely before the 

 arrival of the pollen-tube at the corpusculum, whilst in 

 Pinus canadensis, Picea Larix, and in Larix, one or two of 

 the vacuoles in the middle of the corpusculum usually last 

 until the moment of impregnation. In Pinus canadensis, 

 Picea Larix, and Larix, the free cells which float in the in- 

 terior of the corpuscula, i. e., the germinal vesicles, appear 

 almost all undivided until impregnation (PL LXII, fig. 1); 

 in a few cases only in Pinus canadensis and Larix, indivi- 

 dual germinal vesicles are found more or less entirely filled 



* In the later stages of development of the corpusculum ; In the earlier con- 

 dition strings of granular mucilage radiate from the nucleus. 



f As is the case round the primary nucleus of the embryo-sac of Asphodelus 

 luteus and Funkia ccerulea. See pp. 10 and 13 of my ' Eutstehung des Embryo 

 der Phanerogamen.' 



