Seed in the Sc i i amine ae. 
9 
the evidence of the accompanying figures (Figs. 5-8) seems 
conclusive that such is not the case ; and I am fully con- 
vinced after careful study of a large number of preparations 
that the above description of the development of the em- 
bryonal cavity is the correct one. It is probable that 
Hegelmaier was misled by a section somewhat out of the 
median plane, from a seed in the stage represented by Fig. 7, 
which would show two cavities separated by the tissue which 
surrounds the narrow neck. A comparison with Fig. 6 shows 
that there is one continuous cavity before the widening of the 
apical part of the sac, and such a section as that supposed is 
possible only after this widening. 
The adult seed of C. indica reaches a length of 9 to 10 mm., 
but, as may be seen from the above table, the preponderating 
growth of the chalazal part ceases when about half the final 
length of the seed has been reached. After this time the 
proportion between the two parts does not vary greatly. As 
the seed grows, the original ovular integuments form smaller 
and smaller portions of the whole, and in the ripe seed they 
occupy only a small region at the micropylar end. Here 
they furnish the tissue from which the seed- coat is differen- 
tiated, while the remainder of the testa is formed from the 
external chalazal tissue. Between the seed -coat and the 
embryo-sac is a mass of tissue which, in the ripe seed, con- 
tains starch, and has been called perisperm. It is, perhaps, 
not necessary to give it any other name, though the usual 
definition of perisperm as a storage-tissue derived from the 
nucellus does not include it. This development of the bulk 
of a seed from the chalazal portion of the ovule is a rare and 
remarkable phenomenon, although Kayser ( ; 93 ) has described 
somewhat analogous features in the development of the seed 
of Tropaeolum. It is difficult to conceive what influences 
can have brought about so peculiar a modification in a few 
isolated cases. 
Having now obtained a view of the general course of 
development in Carina, we may proceed to examine its his- 
tological details. 
