Chondriosomes [Mitochondria) and their Significance. 173 
to Selaginella and Isoetes as a third Pteridophyte in which the 
archesporial cell contains a single plastid. He found that in 
Funaria the behaviour of the plastids in gametogenesis exactly 
resembled that previously described by him for sporogenesis; each 
cell of the young antheridium contains numerous plastids but the 
number is reduced to one in the antherozoid mother cell; and in 
this plant each plastid arose from a pre-existing plastid, there being 
complete genetic continuity of the plastids throughout the life- 
cycle. He also suggested that, as he could find no other deeply 
staining body and no radiations, the structure described as a 
blepharoplast or centrosome is, in Mosses at any rate, simply the 
plastid of the antherozoid, the cilia being derived from the ordinary 
cytoplasm. In a later paper Sapehin (1913) considers the relation 
between chondriosomes and plastids, and describes the occurrence 
of chondriosomes in all the mosses investigated (species of 
Polytrichum, Funaria, Bryum, Milium) —Rudolph’s failure to find 
them in Milium he attributes to the use of an unsuitable fixative; 
they occurred in almost every cell of the gametophyte and sporophyte 
but were especially abundant in the protonema, the apical cell of 
the stem, the germ cells, embryo and spore. However, the plastids 
occurred side by side with the chondriosomes, and the two 
structures were apparently quite unrelated. 
Finally, Scherrer (1913) has made a thorough investigation of 
Anthoceros Husnoti and A. punctatus. As he points out, it would 
be difficult to find a plant so admirably adapted for the purpose in 
view as Anthoceros with its thin thallus (enabling rapid penetration 
of fixatives), the single large chloroplast in each cell, the absence 
of oil-bodies and the almost entire absence of fatty material in the 
cytoplasm, and the fact that in the slender sporogonium all stages 
in development of the capsule may be traced in a single section. 
He found that while every cell of the thallus contains a chloroplast, 
this is derived by division from a pre-existing chloroplast, as is also 
the case in the sporogonium ; that all the cells of both sporogonium 
and nearly all those of the gametophyte contain chondriosomes, 
which are absent however from the apical cell and usually also from 
its youngest segments ; that the chondriosomes, which have the 
same forms as in higher plants, increase in number with the age of 
th? cell in passing backwards from the apical cell; that the 
chondriosomes are especially numerous in the thallus cells 
surrounding the iVosfoc-cavities and those around the sporogonial 
haustorium as well as those of the haustorium itself, probably 
indicating that they play a role in nutrition ; and that in this plant 
at any rate there can be no question whatever of any morphological 
relationship between chondriosomes and chloroplasts. 
The General Question of the Origin of Chromatophores 
in the Higher Plants. 
Since the work of Pensa and Lewitsky has opened the question 
of the origin of plastids, in the higher plants particularly, it may 
not be out of place here to consider briefly the general position 
with regard to plastids and their origin in the cell and ultimately in 
the fertilised oosphere or zygote. 
