On Azolla and Salvinia. 235 



Following the development of each from this period sepa- 

 rately, it will be found that the grumous mass of the smaller 

 secondary capsules gradually becomes smaller, while the 

 number of the trifacial cells becomes visibly increased ; until 

 the whole or greater part of each secondary capsule is filled 

 with them and with grume (PL 18. /. 27,); and latterly by 

 trifacial cells alone. After this however, the cavity of these 

 secondary capsules becomes again filled with grumous 

 matter developed from the inner paries of each from 

 several points, each including a variable number of the ad- 

 jacent trifacial cells (PL 20./. 1. 2.) These at length meet 

 in the centre and form a solid mass, imbedded in which, 

 without any appreciable order,* will be found all the tri- 

 facial cells of the capsule (PL 20. f. 11.) 



In the perfect state these s. capsules are exceedingly 

 numerous, attached by capillary simple pedicels to branches 

 of a central receptacle (PL 20. /. 6.) They are of a 

 brownish colour, the cells composing them are in one layer 

 and are separable from each other (PL 20. f. 9.) Each 

 contains a sub-globular whitish opaque body, with an 

 unequal surface presenting prominent and depressed 

 parts (PL 20. /. 10.) It can scarcely be considered as or- 

 ganically cellular, although its surface to a greater or less 

 extent appears cellular under the microscope, for pressure 

 destroys this appearance, and it then appears as uniform 

 grume in which are imbedded the trifacial cells. These are of 

 unequal size ; some of them can be seen without using pres- 

 sure ; they are of unequal size, and of a yellowish brown tinge. 

 Though previously empty they now contain grumous coagula 

 cohering to the sides ; the larger present in addition granules. 



The trifacial cells often appear grouped. No oil escapes 

 on pressure, or I should have attributed the superficial cellu- 



* But I have remarked that while the trifacial cells are being imbedded the 

 trifacial surface is turned to the periphery. Can this have any reference to ger- 

 mination ? 



