602 Mr. Valentine's Supplementary Observations on 



& 18.). This connexion is, perhaps, in most instances dissolved at an early 

 period, and the sporules recede a little from each other, but are still kept in 

 the triangular form by the mother-cell (Tab. XXXV. fig. 13.). It is not un- 

 common, however, to find the connexion unbroken after the sporules have 

 arrived at maturity; and in these instances there seems to be a general adhe- 

 sion at the opposing faces of the sporules (Tab. XXXV. fig. 17.). When 

 these adhesions are broken by violence, the adherent surface of the sporule is 

 seen to be transparent, and altogether deficient of the granular deposit which 

 covers the rest of the sporule, and the three radiating lines are most easily 

 seen in this state of the sporule (Tab. XXXV. fig. 18.). The mother-cell 

 remains entire until the sporules have nearly arrived at maturity, but as to 

 what finally becomes of it I have no evidence. When it is ruptured by ex- 

 ternal violence it assumes a shrivelled appearance, as if it had been on the 

 stretch and had contracted on the removal of the distention (Tab. XXXV. 

 fig. 15.). I have observed several instances in which the mother-cell contained 

 but one sporule, which was in all the cases round, and did not exhibit any 

 signs of a stalk or of radiating lines on its surface (Tab. XXXV. fig. 16.). 



I shall conclude this paper with some observations on the analogy that 

 exists between sporules and pollen, which is so remarkable, and the particu- 

 lars so numerous, that the essential identity of the two can, as I conceive, be 

 scarcely a matter of opinion. In the first place, the sporules are formed in 

 thecse which have a great resemblance to some anthers. They are in most 

 instances surrounded by a pericheetium, which is a collection of modified 

 leaves analogous to the perianth. They are either sessile, or seated on a stalk 

 or seta, which may be named the filament. In Sphagnum the theca is elevated 

 on a pedicel or leafless prolongation of the axis, of which peculiarity the anther 

 of Euphorbia is a parallel instance. The thecae are one-celled, yet they have 

 a columella, which may be likened to the connectivum ; and although the 

 connectivum usually divides the anther into two cells, Callitriche is an in- 

 stance in which tliere is but one cell ; and there are examples in which the 

 cavity is spuriously divided into four cells, as in Tetratheca, which in this 

 respect resembles the theca of Polytrichum ; and in the fact of evacuating its 

 contents by a single pore, resembles the general structure of thecse. All thecae 

 are lined by a distinct membrane, and so nearly does this resemble the endo- 



