MISS E. S. BARTON ON NOTHEIA ANOMALA. 419 
at intervals in no partieular order, each branch again throwing 
out smaller branchlets. These taper considerably both at their 
apex and at their point of connection with the stem, giving the 
whole plant a rather fragile appearance (Pl. 12. fig. 1). 
The thallus of N. anomala consists of three layers of tissue, 
as in Turbinaria and other members of Fucacex. The centre is 
occupied by the usual strand of elongated cells having very thin 
transverse and thick longitudinal walls. The breadth of this 
strand increases with the age of the plant, and in the oldest 
portions of the thallus the thick walls become much pitted, 
while other filaments arising from them intertwine irregularly 
among them (Pl, 12. figs. 2 & 3). These filaments, or * hyphæ " 
as Prof. Oltmanns calls them, have been described and figured 
by him for Ascophyllum nodosum (** Beitr. z. Kenntn. der Fuca- 
ceen," Bibl. Bot., Heft 14, 1889, pl. x. fig. 1). The layer imme- 
diately surrounding the central strand consists in the young 
plant of roundish cells with pits in their walls, and as the thallus 
inereases in age the cells become longer and the walls thicker, 
thereby showing up in marked contrast the thin places in the 
cell-walls (Pl. 12. fig. 25). The cortical layer shows the usual 
narrow, radially elongated cells. 
The growing-point of N. anomala does not lie at the base of a 
depression as in many of the Fucacex, but forms the topmost 
point of the thallus. It consists of three apical cells, as has 
been shown by Dr. Gruber (7. c.), who figures the growing-point 
both in transverse and longitudinal section, and compares it with 
that of Hormosira, which has three or, more often, four apical 
cells. My own conclusions with regard to the apex of Notheia 
were, as stated above, different from those of Dr. Gruber, since 
I believed that there was but one apical cell; but after reading 
his paper and re-examining the series of sections, there is no 
doubt as to the correctness of his decision. The division of 
these apical cells takes place, according to Dr. Gruber, by the 
cutting off of cells at the periphery, and these then divide by 
radial and basal walls to form the various layers of tissue. 
Immediately below the apex of N. anomala may be seen the 
first appearance of young cryptostomata, also described by 
Dr. Gruber. They arise in the usual way by the arrested growth 
of one of the epidermal cells, which at once produces a hair with 
a large basal cell (Pl. 13. fig. 4). "The depression enlarges by 
longitudinal division and subdivision of this arrested epidermal 
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