298 Johnson. — Sphaerococcus coronopifolius , Stackh . 
function. Schmitz states that a closer investigation of their 
fate shows them to be sterile and not connected with spore- 
formation. This conclusion will throw doubt on the accuracy 
of my statement. Still all the observations I have made in 
Sphaerococcus support my view, and in addition it should be 
stated that in no other genus of the Florideae ( Gracilaria 
excepted) is a fusion of the individual cells of a procarpium 
known to take place to such an extent 1 . 
As the development of the fruit proceeds its size increases 
until there is a clear indication to the naked eye of its 
presence, in the form of a spherical swelling. As a fruit 
may arise from any one of the procarpia scattered through 
the whole length of a procarpium-branch, and as this branch 
may be quite short when fertilisation occurs, it is easy to 
explain the earlier descriptions of the cystocarp of Sphaero- 
coccus taken from an external examination of the plant. 
‘ Fructificatio, tubercula minutissima, modo sessilia, modo 
pedunculata, in ramulis extremis sita, atro-purpurea 2 .’ The 
fruit-sheath (pericarp or involucre) is derived from the cortex 
of the procarpium-branch, and is thus present before the fruit 
begins to form. The fruit-cavity is a result of the arching 
of the pericarp and of an increase in the distance between 
the lateral cellular branches of the joint-cells of the central 
axis. Lysigeny does not occur, schizogeny strictly speaking 
occurs to only a limited extent ; the fruit-cavity is due 
rather to the increase of the space between the cellular 
branches which have been free from one another at their 
1 Schmitz, op. cit., p. 23, says, ‘Perhaps, also, in some of these forms (Rhodome- 
leae) a plurality of auxiliary cells may be formed in the individual procarpium ; but 
I have hitherto never been able to demonstrate such a case with certainty.’ Again, 
in a footnote on p. 20, Schmitz says : ‘ This point [the conjugation of the fertilised 
ovicell with the nearest auxiliary cell] in the development of the fruit of the 
Corallineae (the exact investigation of which is, as is well known, rendered re- 
markably difficult by the small size of the cells), I have hitherto been unable 
to establish directly. Moreover, not only in the Corallineae, but also in many other 
Florideae with small-celled, closely packed cellular tissue, there are special diffi- 
culties opposed to the exact ascertainment of the fate of the fertilised ovicell which 
render these investigations extremely troublesome and tedious, and greatly hinder 
any certain decision.’ 
2 Good, and Woodw., in Trans. Linn. Soc. iii. p. 185. 
