40 AKT. 4. — A. YASÜDA I ON THE 



The periderm is well-developed and forms a thick layer around 



the tuhers. 



The sclerenchjnna of the tubers is best developed in Tricho- 



santhes cucumeroides, where it forms an almost continuous ring. 

 In Trichosanthes mnltlloba the development of the sclerenchyma 

 is somewhat checked and in Trichosanthes japonica it is very 

 much retarded. The size of the sclerenchymatous cells and the 

 thickness of their walls are much greater in the first two species 

 than in the last. For the sake of a comparison I give the follow- 

 ing numbers obtained from the measurements of the large scleren- 

 chymatous cells in the tubers of the above three species : 



nhimeter. ïliickness of the wall. 



Trichosanthes multiloba 0.080 mm. 0.020 mm. 

 T cucumeroides 0.050 ,, 0.020 „ 



T. japo7iica 0.030 „ 0.008 „ 



The fibro-vascular bundles are most reduced in Trichosanthes 

 cucumeroides, where many of the vessels are separated from each 

 other. The following are the diameters of the large sieve-tubes 

 in each species : 



Trichosanthes multiloba 0.070 mm. 



T. japonica 0.050 „ 



T. cucumeroides 0.045 „ 



Diameters of the large vessels : 



Trichosanthes multiloba 0.42 mm. 



T. japonica 0.35 ,, 



T. c2ic2imeroides 0.30 ,, 



The starch-grains contained in the tubers attain their 

 maximum size in Trichosanthes multiloba, those of Trichosanthes 

 japonica coming next, and then those of Trichosanthes cucumeroides. 

 In point of size the starch-grains from the tubers of Trichosanthes 

 multiloba, however, stand second among those contained in the 



