DEVELOPMENT OF CONCEPTACLE IN THE FUCACE^. 37 
from one another. An intercellular canal” is thus formed, 
stretching through the limiting tissue into the cortical tissue. 
He further tells how the cavity thus formed becomes flask 
shaped, and the cells which line it put out papillae, which 
further develop into hairs. He assigns to the conceptacle 
a similar history, and hence concludes that it is ‘‘ homolo- 
gous” with the Fasergrubchen.” Though he records 
observations on a considerable range of allied plants, he finds 
no noteworthy deviation from the type of Fucus vesciculostis. 
He gives no figures illustrating these observations. 
Luerssen Handbuch der Syst. Bot.,’ 1879, Bd. i, p. 105) 
gives a different history. He says small spots of the surface 
of the thallus are so overgrown by the surrounding tissue 
that only a narrow opening remains. 
Thuret does not mention the subject of development of the 
conceptacle in any of his publications to which I have had 
access. 
Preliminary Pemarks. 
Many of my preparations of Fucus serratus were made 
from materials collected in August, 1878 ; these were treated, 
while fresh, with a dilute solution of chromic acid in water, 
and afterwards preserved in alcohol. The results obtained 
from these materials have been verified in other specimens, 
collected in August, 1879. These were preserved in a satu- 
rated solution of common salt, and then hardened in alcohol. 
The latter method of preparation has been used for all the 
other plants of the group with which I have worked. The 
sections were in all cases mounted in glycerine and acetic 
acid. 
The youngest stages of development of the conceptacle are 
naturally to be found close to the apex of the branch, and 
only on those branches which still retain an active apical 
growth. Such branches may be recognised by their possess- 
ing a well-marked depression at the apex. 
Regarding the sexual conceptacle as the type of such 
structures, I have studied the development of it first, and 
tlien compared with it the development of the “ Faser- 
griihehen,” which I regard as an incomplete sexual 
conceptacle. 
In describing the planes of section relative to the thallus, 
I use the terms vertical longitudinal section ” and trans- 
verse section ” in the same sense as Rostafinski Beitriige 
z. Kennt. d. Tange.,’ Heft, i, 187G, p. 17), the former being 
a longitudinal section in a plane perpendicular to the 
fiattened sides of the thallus; the latter cutting the organic 
axis at right angles. 
