Stopes and Fujii, The nutritive relations of the surrounding tissues etc. 19 
• the endosperm tissues does not necessarily mean that no soluble 
food passes through these cells to the egg cell, yet when cells 
become packed with stored food their chief function ceases to be 
that of passage cells, and the stored food itself is certainly not 
available in tliat form. So far as we can judge by tlie results 
obtaiued by treating living material with Gujac resin, the jacket 
cells secrete oxydase and diastase which dissolves the starch in the 
neighbouring cells as it is reqnired by the egg. Further. we have 
observed how the endosperm cells surrounding the egg gradually 
lose their starchy contents as the egg cell grows (cf. hg. 8). 
A similar solution and disappearance of the protein grains in the 
endosperm also takes place and we think it is probable that 
proteases are also secreted by the jacket cells, but as yet 
unfortunately we have been unable to demonstrate their actual 
presence in these cells. 
The regülarity of the arrangement of the jacket cells, their 
large nuclei and thick cytoplasm rieh in granulär contents, all 
unite in supporting the view that they are glandular or secretory 
in nature, and act as go-betweens for the egg cell and the Stores 
of food in the endosperm cells. To some of the very fine well 
marked granulär bodies present in large numbers in the jacket cells 
we may look for the proenzymes or zymogenes. 
It is interesting to compare this view of the jacket cells with 
the results of some observations on Angiosperms in which the 
antipodal cells are found to have an important part to play in the 
passage of food to the egg cell. Westermaier’s * 2 3 4 ) original view 
that the antipodals in the Raminculaceae had an important nutritive 
function, was followed and confirmedby Osterwal der 2 ), Goldflus 3 ), 
Ikeda 4 ) and Lötscher 5 ) in other groups of Angiosperms. By all 
these workers the antipodals are supposed to have the power of 
obtaining for the egg cell and of passing on to it the food materials 
which are present in the surrounding tissue. It is to be remembered 
that phylogenetically the antipodals are generallv supposed to represent 
the reduced prothallium tissue; so that antipodals and jacket cells 
are in a way homologous. The present existence and differentiation 
of the Antipodals in some Angiosperms is due to their similar 
physiological function performed by tliem, and which corresponds 
with that of the more definitely organised jacket layer in Gymno- 
sperms. 
When we come to the Pines we find the jacket cells less 
strongly differentiated than in the Cycads and Ginkgo, which we 
Westermaier, M., „Zur Embryologie d. Phanerog. . . . u. d. sogeD. 
Antipoden“. (Nova Acta Acad. Leop. Carol. 57. 1. 1890.) 
2 ) Osterwalder, A., „Beitr. z. Embryol. v. Aconitum Napellus’ 1 . (Flora. 
85. 1898. p. 254—292.) 
3 ) Goldflus, M., „Sur la struct. et les fonct. de l’assise epithel. et d. 
antipod. chez 1. Composees“. (Journ. d. Bot. 12. 1898 and 13. 1899.) 
4 ) ikeda, T., „Studies in the physiolog. funct. of antipodals in Trycirtis 
hirta“. (Bull. Coli, of Agricult. Tokyo Imp. Univ. Toi. V. 1902.) 
5 ) Lötscher, P. K., „Ueb. d. Bau u. d. Funkt, d. Antipoden in d. 
Angiosp“. (Flora. Band 94. 1905. p. 213—262.) 
2* 
