INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 979 



cell-wall in this plane and arrange themselves into the nuclear plate 

 which, in Tradescantia zebrina, has the form of a ring, and in other 

 species of Tradescantia of an absolute flattening of the differentiated 

 nucleus. 



3. The point where the centres of attraction appear to be shifted. 

 The nuclear elements are now drawn to the opposite poles of the cell, 

 their separation being thus determined into two distinct groups or new 

 nuclei. 



Multinucleated Cells in the Suspensor of Dicotyledons.* — In 

 pursuance of recent discoveries by the author himself, Strasburger, 

 Treub, Schmitz, and others, t of the existence of a plurality of nuclei 

 in vegetable cells, Hegelmaier has closely examined and described a 

 similar phenomenon in the suspensor (pro-embryo) of certain dicoty- 

 ledons belonging to the tribe Vicie^ of Leguminos;c. The species 

 specially examined were Pisum saticum, Lathyrus sylvestris, odoratus, 

 Ochrns, pratensis, stans, Aphaca, and Nissolia, Orobus vermis, niger, 

 tuberosus, and atbus, Lens esculenta, Vicia sepium, pisiformis, and 

 tenuifolia, and Cicer arietinum. Of these the last is the only one 

 that presents any important differences from the rest. 



The peculiarity presented by all the species above mentioned, and 

 probably by all belonging to the tribe, is that the fully developed 

 suspensor, which is of considerable length, is always composed of 

 the same number of cells, viz. four ; exceptions to this being rare 

 abnormalities. The structure consists of two parts, each composed of 

 a pair of cells. At full maturity the cells of the apical pair are 

 swollen out, and closely adj)resserl to one another with flat surfaces, 

 so as to form a roundish ellipsoidal or nearly spherical ball. They 

 contain a somewhat coarse-grained protoplasm forming a parietal 

 layer of variable tliickness, imbedded in which are large nuclei 

 placed at uniform distances, the number of these nuclei appearing to 

 depend on the size of the ball, which varies with the species. The 

 average number is perhaps from twenty to thirty, at least in species 

 with large flowers and seeds ; in Lens esculenta there were found 

 only from twelve to sixteen, in Vicia tenuifolia about eight, and in 

 Lathyrus stans and Nissolia only four. When, as in Lathyrus sylvestris, 

 these cells are smaller, the number of nuclei is still consideral)lo. 



The two basal cells of the suspensor form, as it were, a kind of 

 })edicel to the capitulum ; its cells are much narrower, and taper off 

 gradually to the base. The number of nuclei in these cells is still 

 larger, and dt^pends on their size. In the upper, broader part of the 

 j)cdicel tlu:y are imbedded, at uniform distances, in the parietal proto- 

 plasm ; in the lower, narrower part they are arranged in several rows ; 

 in the narrowest basal portion the protoplasm is no longer in the 

 form (if a parietal layer, but is a mucilaginous mass occupying nearly 

 the whole of the cell-cavity. 



The form of the nuclei presents nothing remarkable ; in each, 

 when mature, is a large, strongly refractive, and sharply defined 

 nucleolus. In old nuclei two nucleoli are occasionally found. 



• ' IW. Z(it.,' xxxviii. (ISSO) p. UVX 



t iSco thia Journal, ii. (187l>) i). GOO, and miL-, pp. Ill, 303, 482, 493. 



