Linnean Society. 499 
tubes attenuated towards each extremity, and filled at first with an 
almost colourless coagulable protoplasm. After a short time starch 
globules are seen within them, which might readily be mistaken for 
the rudiments of the spiral fibre; but the author believes that the 
accounts given by some writers of the formation of spiral fibre in 
spiral vessels from rows of minute granules are incorrect, and have 
arisen from observation of starch granules lying in rows often 
running obliquely across the tubes. After a greater enlargement 
in the length than in the diameter of these cells the starch granules 
and finally the protoplasm disappear, and faint streaks denoting the 
nascent fibres are at length visible upon the walls. These gradually 
become more and more distinct, until in the mature elaters they pre- 
sent themselves in the form of strong flattened bands. In Marchantia 
there are two fibres, the ends of which are confluent at the extremities 
of the tubes in which they are contained; so that more properly 
speaking there is but one endless fibre twisted upon itself, which 
may be represented by a piece of string doubled with its ends 
united, and twisted spirally upon itself. This is evidently the best 
possible condition of structure for its purpose of acting as a spring. 
In unrolling, the fibre tears up the membrane of the walls of the 
tube, which after the elaters have been discharged is often no longer 
to be detected. 
While the elaters are passing through these stages the larger 
elongated cells exhibit a very remarkable series of changes, which 
Mr. Henfrey regards as differing from anything that has yet been 
observed in analogous structures. They are at first filled, like the 
elaters, with a delicate colourless protoplasm, in which float ex- 
ceedingly minute granules, and which is apparently the same sub- 
stance that occurs in all young cells which increase by self-division. 
These larger cells soon exhibit transverse streaks of a lighter colour, 
in consequence of the separation of the protoplasm into a number 
of distinct portions, and the formation of cross membranes at these 
places, dividing the tubular ceil into a row of cells, all of a square 
form except the two terminal ones which are attenuated towards the 
free point. The author could not determine whether the septa were 
formed by gradual growing in of the membrane, nor could he detect 
at this period a double membrane, which must, however, exist, to 
admit of the subsequent separation of the contained cells. Vertical 
septa are often formed in addition, producing a double row of cells 
within the tube. About the time when the cells separate from each 
other, their contents undergo a change, which exactly resembles 
that which occurs in the contents of the parent-cells and special- 
parent-cells of pollen when the formation of free cells is about to 
take place in their interior. The mucilaginous matter, or protoplasm, 
acquires a deep yellow colour, becomes much thicker, and exhibits a 
quantity of globular bodies which look like drops of oil. Mr. Hen- 
frey gives his reasons for regarding these appearances neither as 
drops of oil nor as vesicular cavities, but as globular drops of the 
yellow protoplasm. Such globules are of various sizes and some- 
times occupy half the cavity of the cell, but neither before nor after 
32% 
