EXPLANATION OF THE PLATES. 267 



Fig. 24. A very young leaf of Crassula portulaca, the five 

 cells which solely compose it being still surrounded 

 by a parent-cell. 



25. Three cells from an articulated hair of potato, with 

 a retiform current of mucus upon their walls. In 

 the central cell the direction of the currents is par- 

 tially indicated by arrows. 



In all the instances in which I have observed the movements in the cells of phse- 

 uogamous plants, I have constantly found the moving matter to consist of a j'ellowish 

 mucous fluid, perfectly insoluble in distilled water, and mixed with minute black 

 granules, but differing entirely from the other aqueous sap of the cells ; and even 

 when the currents were so small as to appear merely as excessively mhmte delicate 

 lines of black points, I succeeded with higher magnifying powers in distinguishing 

 the yellowish mucous fluid, especially when aided by the favorable circumstance 

 (which not unfrequently occurs) of the current becoming arrested by some impedi- 

 ment, which causes a somewhat larger quantity of the moving material to accumu- 

 late, and is generally followed either by a change in the direction, or a division of 

 the current. 



PLATE II. 



Fig. 1. Cells from the epidermis of the pericarp of Ocymum 

 basilicum, moistened with water, so that the mucous 

 globule has expanded, and torn the outer cell-wall 

 (a) from the side walls {b). 



2. Cells from the pericarp of the epidermis of Ziziphora 



dasyantha. 



3. Cells from the pericarp of the epidermis of Salvia ver- 



ticillata. 



4. Cells from the pericarp of the epidermis of Salvia 



Horminum. 



5. Cells from the pericarp of the epidermis of Salvia 



Spielmanni. 

 2, 3, 4 and 5, a, exhibit the remains of the side-walls of 

 the ruptured cells. 



6. A portion of the epidermis [a) and of the integument 



{b) of the ovule of Collomia coccinea. The epidermis- 

 cells contain merely granules of starch. 



