60 



author evidently considers to be essentially identical, are exceedingly 

 interesting. 



" In the first place, tte sporules are formed in thecae which have a great resem- 

 blance to some anthers. They are in most instances surrounded by a perichaetium, 

 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 peculi- 

 arity 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 instance in 

 which there 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 endothecium of an anther, that in Jungennannia multi- 

 fida its tissue is fibrous. The remarkable manner of the development of sporules and 

 pollen is a most convincing analogy ; they are developed in unions of fours in the ca- 

 vities of simple cellules ; in fact, they are secretions in the cellules which occupy the 

 interior of the theca or anther, and are the only instances on record within my know- 

 ledge, of organized secretions in the cavities of simple cellules. Although the tetra- 

 hedral union of both sporules and pollen is almost always dissolved at an early period, 

 yet in some instances, as in (Edipodium and Erica Tetralix, it remains at maturity. 

 Again, neither sporules nor pollen ever have the slightest apparent organic connexion 

 with the parent plant, — a most remarkable coincidence, and a fact which has never 

 been insisted on as a distinguishing character between sporules and seeds." — 502. 



The effects produced by the application of sulphuric acid to the 

 sporules are next described ; " the same phenomena occur as when it 

 is applied to pollen." The author in a foot-note recommends this acid 

 as " a valuable agent in the analysis of the peristomes of mosses," and 

 thus concludes his valuable letter : — 



*' Lastly, to complete the analogy, the sporules of mosses and of some other tribes 

 commence their germination by the emission of the internal lining membrane in the 

 form of a tube, which is exactly analogous to the pollen-tubes. In the mosses these 

 tubes increase by the addition of a series of fiesh tubes at their extremities, and at 

 length a bud containing the rudiments of stem, leaves and roots is formed, which may 

 be considered analogous to the embryo or young bud in the seed of the more highly 

 organized plants." — 506. 



The beautifully engraved illustrations which accompany the paper, 

 comprise figures of GEdipodium Griffithianum, both of the natural size 

 and magnified, and highly magnified views of the sporules in various 

 stages of development, of the theca, and other parts of that moss ; 

 and also figures exhibiting the effects of sulphuric acid on the spo- 

 rules of Gymnostomum truncatulum, Orthotrichum striatum, and Jun- 

 gennannia complanata. 



(To be continued). 



