March, 1907.] Cymathere, a Kelp from the Western Coast. 
9 1 
a coast where it is well developed its young plants may be seen 
everywhere between the tide marks even up as high as any of 
the kelps grow, where they must soon perish because of the 
unsuitable conditions. They are much the most abundant of 
all the young kelps to be found even in high levels. The young 
of Cymathere though it grows much closer to the tideline than 
Nereocystis, are not often found growing uncovered at low water 
and are very much less abundant though the adults are by no 
means scarce at Port Renfrew. 
In its histology Cymathere offers some points of interest. As 
to the presence or absence of mucilage ducts there seems to be 
some question since De Toni '95 contradicts Kjellman ’93 by 
asserting that they are present. In the specimens which I have 
examined the stipe is wholly without ducts of any kind, while 
m the lamina there occurs an irregular circle of openings which 
mav be considered mucilage ducts. But they are not definitely 
developed tubules with a lining wall of special secreting cells as 
MacMillan ’99 reports in Nereocystis; nor are they in a closely 
crowded circle of definite position as in Laminaria bongardiana 
or in L.- bullata as figured by Miss Mueller ’04, fig. 8. They 
appear rather as a local gelatmization and breaking down of 
certain cells, perhaps the beginning of degeneration. To the 
writer it seems most likely that their presence or absence is a 
verv variable character which might not appear in younger,more 
vigorous material. This if true would explain the disagreement 
of the authorities cited. A similar breaking down of certain 
cells mav sometimes occur in Renfrewia parvula but very much 
less abundantly. In this case I did not consider the cavities 
thus formed mucilage ducts because they seemed simply path¬ 
ological alterations of the tissues and not normal occurrences. 
In places the inner cortex is developed into thick walled 
strengthening tissue as is usual in the family. It is of such 
sclerenchyma that the ribs on the folds are formed and to it they 
owe their strength. The greater thickness of the ribs beyond 
that of the rest of the lamina is entirely due to the extra develop¬ 
ment of this tissue. 
The development of the sporangia follows closely that of 
other kelps. MacMillan’s ’99 figures of the early stages of their 
development in Nereocystis might almost bave been drawn from 
mv own preparations of Cymathere. The separation of the 
pellicle from the sorus takes place after the following fashion: 
The outer cell walls of the epidermis of the unaltered lamina 
form a rather thick cuticle over the surface. When the epider¬ 
mis divides into the two layers which go to form the paraphyses 
and the sporangia, the daughter cells secrete for themselves new 
cell walls, at least on the external and lateral faces, leaving the 
old cuticle with the partitions between the cells, free and hang¬ 
ing to the lamina only by the bases of the latter. On the elon¬ 
gation of the paraphyses these connections are broken and the 
