244 Canadian Record of Science. 



upon the upper side of the tendril. It thus appears that the 

 hairs are chiefly developed in the regions where the sensi- 

 tiveness of the tendril is least, that where this latter is 

 most acute the surface is the smoothest. 



In the distribution of the vibrogen bands, there is proba- 

 bly greater variation than in any other particular noted. 

 While in Cucurbita pepo, we have noted three bands of this 

 tissue, we cannot consider this strictly true of the whole 

 genus, since in C. pyxidaris there are four such at the tip. 

 This is also true of other genera. In Sicyos and Cucumis 

 there are more than four bands at the base, but, by absorp- 

 tion or merging, they become two at the tip. In Lage- 

 naria four bands are distinct throughout, but in Citrullus, 

 Cucurbita and Megarrhiza they become reduced from four, 

 at the base, to three or (Citrullus) two. On the other hand, 

 in Luffa, Rhynchocarpa, Benincasa, Megarrhiza and Cucur- 

 bita, the three bands at the base become four at the tip. 

 The general tendency appears to be toward the develop- 

 ment of three principal bands at the base, together with 

 several subordinate bands which soon disappear. The former 

 become divided into four at about the middle section of the 

 arm. In all such cases, the lateral bands remain intact, 

 while the division occurs in the central band, but in such a 

 way that its halves, though distinct, are not widely sepa- 

 rated, and in their relation to the lateral bands still act as 

 one. Before division, the central band is usually equal in 

 width to each of the laterals, a relation, in point of size, 

 which is preserved even after division, so that this band, at 

 its divided extremity, is incapable of exerting a stronger 

 influence over the others than does its undivided base. 

 These facts have an important bearing upon what has else- 

 where been stated, 1 with reference to the circumnutations 

 and the relations which the bands bear to them. It may 

 also be noted that, in most of the tendrils observed, free 

 torsion was common and conspicuous. 



Tensile Strength. — For the determination of the tensile 

 strength of the tendrils during and after coiling, three 



1 Trans. E. Soc. Can., IV. 



