18 Stopes and Fujii, The nutritive relations of the surrounding tissues etc. 
already enumerated, we find that the following brief account holds 
good for all the cases we observed. 
The egg cell, which acts as a point of attraction for the food 
stuffs, is supplied with solnble food passing in throngh the 
endosperm. While it is young and growth is rapid apparently the 
supply does not very mach exceed the demand and no food is 
deposited in solid form. Later however the balance is reached 
and so soon as the supply becomes greater than the demands of 
the growing egg deposition in solid or semisolid form begins round 
it. In the case of stareh, deposition cihvays takes place first in the 
cells of the endosperm at the base of the archegonia. In different 
groups the relative time of deposition and the state of development 
of the egg may vary greatly, for example in the Cycads and Ginkgo 
both stareh and protein substance are largely deposited in the 
endosperm before the growth of the unfertilized egg is completed, 
but in Pmns deposition is extremely slight in the endosperm even 
after the embryo lias reached a considerable size. 
In all cases, at some time or times in the course of its 
development we found both stareh and protein substance deposited 
in the egg cell itself. The protein substance is early deposited in 
large grains in the egg of Cycads and Ginkgo , and some grains 
are still present even after the formation of the proembryo. Stareh 
on the other hand is mach more vacillating in the egg, and has 
the appearance of “transitory stareh”, being present in very fine 
grains which are largely of the nature of amylodextrine. Both 
stareh and protein substance are deposited first in The perifery of 
the egg cell, but later tliey are found scattered througliout the 
eytoplasm, probably being carried round by an internal Streaming. 
The formation of transitory stareh grains aiong the perifery of the 
protoplast of the egg is at times very conspicuous, and is certainly 
the result of the conversion of cliosmosable sugars into non- 
diosmosable stareh immediately after the entry of the former into 
the egg cell. Similarly the entering proteid is deposited in grains 
near the perifery. By this means the concentration of the soluble 
food in the egg cell is kept constantly below that of the surroundiug 
cells, which ensures a continual transfer into the egg, and at the 
same time prevents a too great concentration of osmotic substances 
in the egg cell itself. 
If then the process of the entry of food is such as we have indi- 
cated, what is the chief funetion of the jacket layer which is so very well 
characterised, particularly in the lower Gymnosperms? As we have 
already mentioned in the Cycads and Ginkgo the supply of food 
in the early stages is greatly in excess of the demands of the 
growing egg, so that rnuch is deposited in solid form, tili, in fact, 
the endosperm cells are packed with it. Once the food in the 
surrounding cells is laid down in solid form, the egg cell is 
practically cut off from it unless there is some means of renderiug 
it soluble, or transmitting it into easily diosmosable substances; 
and it is here that we think the jacket cells play an important 
part. Though the presence of a large quantitv of stored food in 
