AGGREGATION IN THE TENTACLES OF DROSERA. 309 



would then be mainly remarkable only for their inordinate 

 dimensions, and to form which would have required the co- 

 operation of a very large number of individuals. But there 

 was not a trace of pseudopodia, still less of "axes^'j the 

 whole had a certain degree of *' flow," whilst the hyaline 

 smooth margin here and there pushed out great convex 

 (almost, when very much projected, hemispherical), wave- 

 like expansions, like some Amoebae, but with exceeding slow- 

 ness. There seemed, however, to be evinced no tendency 

 whatever to become encysted. This therefore still remains a 

 problematic production. 



In a future number I propose to continue the consideration 

 of the newly-described Sarcodina, as recorded in the various 

 memoirs. 



The Process 0/ Aggregation in the Tentacles of Dro- 

 sera rotundifolia. By Francis Darwin, M.B. (with 

 Plate XXIII.) 



The term " aggregation " is applied by my father' to 

 the changes which are produced in the tentacles of Drosera, 

 and in certain parts of other plants, by the following 

 agencies : — 



I. The mechanical irritation of the glands by repeated 

 touches or by prolonged contact with organic or inorganic 

 substances. 



II. Similar mechanical irritation transmitted from the 

 glands on the disc to other glands on the same leaf. 



III. The absorption of certain fluids such as solution of 

 carbonate of ammonia, infusion of raw meat, &c. 



IV. Heat. 



V. Osmosis caused by immersion in glycerine, &c. I do 

 not feel certain that this form of aggregation is identical 

 with that due to the previously mentioned agencies, and it 

 will not be further alluded to in the sequel. 



The phenomena connected with these changes have been 

 fully described by my father ; the following remarks are 

 merely intended to bring forward a few questions connected 

 with this subject which have not at present been answered, 

 and which are of importance to any one forming a judgment 

 on the essential nature of process. 



Aggregation occurs both in the pedicel of the tentacle 

 and in the gland which surmounts it ; the present paper 



1 ' Jusectivorous Plants/ Cb. iii. 



