360 Phillips — On the Development of 
descriptions, including his own, had been inadequate. This 
amended description was not however accompanied by a 
figure. 
From among several species of Callithamnion proper which 
I have examined, I give here the early condition of the 
procarp in Callithamnion grannlatum , and one of a later 
condition in Callithamnion byssoides . 
The carpogonial branch in Callithamnion grannlatum 
appears to consist of four cells which are included in a common 
gelatinous envelope with the joint-cell from which it is 
derived. It is probable however that the branch is 3-celled, 
and that the fourth cell is a sterile derivative of the proximal 
cell of the branch. The joint-cell also buds out two cells 
right and left of the carpogonial branch (PL XVIII, Fig. 20). 
In Callithamnion byssoides , the older joint-cells are much 
elongated, and the favella is lax, approaching the condition 
described by Bornet as seirosporic (PI. XVIII, Fig. 21). The 
figure represents a stage immediately subsequent to fertiliza- 
tion, all the procarpial cells being still recognizable. 
The interest consists in the fact that two cells have been 
derived from the carpogonium, right and left, and are in 
apposition with the second cells of the branches from which 
the two-lobed favella is derived. Schmitz, in the later 
description to which I have referred, speaks of the cutting off 
from the carpogonium of a small cell, by means of which the 
conjugation is effected. The figure shows a pair of such cells. 
Again, it is clearly the second cells of the sporiferous branches 
that are the auxiliary cells. First, because the ooblastema- 
cells are in contact with them only, and secondly, because no 
sporiferous threads occur below this point on the branches. 
Judging from the case of Callithamnion byssoides , the genus 
seems to represent a specialized condition among Ceramiaceae, 
differing from the simpler condition represented by Antitham- 
nion Plumula and other species in the 3-celled carpogonial 
branch ; in the formation of two auxiliary cells to each 
carpogonium ; in the occurrence of these auxiliary cells as 
the second cells of lateral branches ; and in the conjugation 
