DEVELOPMENT OF CONCEPTACLE IN THE FUCACE^. 43 
simplest form, the mode of branching which accompanies 
the formation of antheridia (fig. 8, i, ii, hi). 
A single cell grows out to form a papilla. This divides 
(8, i) by a transverse wall. An apical antheridial cell is 
thus formed, which is supported by a single pedicel cell. 
The latter may now continue growth and put out a lateral 
papilla (8, ii), which is functionally equivalent to the 
original papilla. 
In fig. 8, hi, a represents a system of antheridial branching 
of a higher order. i is an antheridium from which the 
antherozoids have already escaped, the primary axis was 
then p — a i, a ii is an antheridium which was formed on 
the apex of a lateral outgrowth below a i. a Hi is the lateral 
papilla which precedes the formation of a third antheridium. 
The whole system is then, in this case, a sympodial system, of 
the type represented by Sachs in his ^Lehrbuch,’ 1874, 
fig. 136, D (cf. 8, iii, b). It is only rarely that the branch- 
ing is as simple as in the cases represented, since it is 
often not confined to one plane, and the antheridia are 
usually more crowded together (compare Thuret’s figures, 
especially in his ^ Etudes Phycologiques,'’ plates xv, 6 ; xxii, 
8 — 10, xxiv, 6). Often the system approaches irregularly 
the type figured by Sachs (loc. cit., fig. c), but, however 
irregular, the antheridial branching seems always to be 
sympodial. 
On the mode of formation of the oogonia I have no remarks 
to offer. 
The difference between the Fasergriibchen ” and the true 
conceptacle is clearly marked in the mature state both by 
the form and the contents. But as we pass back to the 
earlier stages of development the distinction becomes less and 
less, till w^hen we reach the condition in which the formation 
of hairs has begun in neither of them, it is impossible to say 
definitely, from mere inspection of the structure, whether 
the cavities will produce sexual organs or only hairs. 
Still, if we take young plants and study the development 
of the cavities formed at their apex we may, with the greatest 
probability possible in such a case, regard such cavities as 
early stages of the Fasergriibchen.” 
This I have done, and found their development to differ in no 
point of importance from that of the sexual conceptacle. The 
initial and basal cells are present ; the form of the cavity is 
the same. The central column appears just as in the sexual 
conceptacle. 
The hairs themselves are multicellular but unbranched. 
The neck is usually wider than in the sexual conceptacle. 
