Notes . 
39i 
planes of the rings now show irregularities in the number of cut 
ends present at any part of it, and instead of being uniform in size 
and only one cell deep, the size is variable and the numbers may 
be from one to three, — a fact which shows how very considerable the 
overlapping of the ends must be, for as no tangential divisions ever 
take place, the alterations 
are due entirely to the causes 
just described. At a later 
period in development the 
regular outline of the rings 
is distorted by the continued 
slipping of the ends, and the 
wavy outline of the older 
endocarp as a whole is 
partly to be attributed to 
this circumstance. 
During the period of 
lengthening of the cells the 
nucleus, as might have been 
expected, undergoes a 
change in its appearance. 
From presenting anapproxi- 
Fig. 23. Transverse section from nearly ripe 
fruit, a , b, c, The layers forming the endocarp. 
x, The unthickened portion of c in Figs. 21, 
22. d, Innermost layer of pulpy tissue. 
mately circular outline it becomes spindle-shaped and remarkably drawn 
out at the two ends ; it is of a relatively large size, and the whole 
cell is very rich in protoplasmic contents — a feature which would of 
course be looked for in a tissue where metabolism is extremely active. 
Meanwhile a third cell-layer, which lies immediately outside the two 
I have described, has undergone changes, preparatory to its taking part 
in the formation of the stone. And although the modifications which 
arise in it begin at a somewhat later period than those in the inner 
cells, they advance with great rapidity and soon cause this portion 
of the endocarp to be the most striking of all in appearance. The 
cells which compose it are much larger in transverse section (2-3 
times) than those lying internally to it ; but, like them, they are very 
densely filled with protoplasm in which a nucleus of a very large 
size is imbedded. The first change which takes place beyond mere 
increase in size, consists in a slight radial extension of the cells, and 
at the same time, just as in the case already described, the nucleus 
alters in form, becoming spindle-shaped, and lies at first somewhat 
