J. M. MACFARLANE ON VEGETABLE AND ANIMAL CELLS. 593 
tion into parts is effected, or the nucleus elongates greatly and becomes con- 
stricted in the middle, as figured by Jonow, one or more nucleoli being enclosed 
in each part. When the nucleus and nucleolus are large, as in the young growing 
peduncle of Hemanthus coccineus and stem of Fritillaria imperialis, one can 
trace this ingrowth towards separation with ease; and it is to be noted that the 
size and number of nucleoli enclosed greatly determine the size of each resulting 
nucleus. Thus we may get, as ingrowth proceeds, a portion with three well- 
formed nucleoli being cut off from a smaller portion with two lesser nucleoli, 
and so on, the nucleoli seeming to act as centres round which the nucleoplasm 
gathered (fig. 10). 
STRASBURGER, in terming this breaking up of the nucleus “ fragmentation,” 
does not regard the nucleoli as. of marked importance. He also holds that it is 
in old cells that this phenomenon is exhibited.; but in very many cases this is 
not so, since even the second, but usually the fourth or fifth internode from the 
apex in Chara, may have two or three large nuclei, and yet be surrounded by 
dividing cells which have been derived from the nodal cell that was cut off con- 
temporaneously with the internode under consideration. The same is. true in 
other plants. But while it may form in comparatively young cells, it remains 
as the permanent condition of old cells ; that: is, the nuclei formed thus: may 
after a time become dormant, and be found in old cells.. This is especially true 
of those which are elongating to form. bast. cells in the more succulent plants. 
After an examination of many plants, I find that the most gradual transi- 
tion in this continued activity can be traced. Thus, in Spirogyra nitida, one 
frequently finds two to five endonucleoli, though rarely two nucleoli; but in S-. 
majuscula two nucleoli are very common. In the succulent parts of most plants, 
one nucleus, with two or at most three nucleoli, each enclosing one to two endo- 
nucleoli, is the rule. In the elongating cells of the internodes of Eguisetum 
limosum the condition is one nucleus with three to six nucleoli, and two to three 
endonucleoli in each.. In a few cells of some succulent plants, as Diclytira 
spectabile, young peduncle of Haemanthus coccineus, Orchis mascula, &c., two to 
three nuclei each, with one to four nucleoli, can be noticed. But in rather long 
cells round the fibro-vascular bundles in Hamanthus coccineus, as many as seven 
nuclei, each with two to three nucleoli, have been detected.. Chara may have 
even more, specially in the internodal cells, each filled with dozens of small 
nucleoli. Again, HEGELMAIER has described the multinuclear suspensor cells 
of some Leguminose as having thirty or more nuclei, with one or two nucleoli 
in each. As already stated, thirty to seventy nuclei, each with several nucleoli, 
is the rule in the internodal cells of Nitella ; while, according to ScumiTz, there 
may be several hundred in the seaweed Valonia, and in other alge and fungi. 
TREUB observed great numbers in bast cells and laticiferous vessels. 
VOL. XXX. PART II. oA 
