59 



to be developed in similar unions, it is most probable that similar lines indicating a 

 valvular dehiscence also exist on them. This is certainly the case in some mosses, for 

 instance, in CEdipodium, and in Isoetes, Lycopodium, and Osmunda regalis; and in 

 those instances where such a structure is not visible, it is probably oveing to a thicken- 

 ing of the membrane, or a deposition of opaque matter on its surface, as in Pilularia. 

 In the mature sporules of Pilularia they can only be discovered by dissection, and in 

 the abortive ones they cannot be discovered at all after the first stages of their growth ; 

 whilst, again, the sporules of Jungermannia complanata exhibit similar lines after 

 they have been submitted to the action of sulphuric acid. After the protrusion of the 

 germ, however, it does appear to be quite immaterial from what part of the germ the 

 first leaves, root or stem shall arise. 



" It is almost superfluous to point out, that these primordial leaves, if the sporules 

 be considered as seeds, have no analogy, except in their use, with cotyledons, because 

 true cotyledons pre-exist in the seed, whereas these are the product of germination. 

 But according to the view of the nature of sporules which I have endeavoured to es- 

 tablish, Pilularia must be considered as nearly allied to monocotyledons in its germi- 

 nation. * * I shall conclude these observations by stating that I have not 

 been able to detect any organs which, as in the mosses, can by any possibility be sup- 

 posed to perform the office of impregnating the sporules." — 492. 



Art. XXXT. — Supplementary Observations on the Development of the 

 Theca, and on the Sexes of Mosses. In a Letter to R. H. Solly, 

 Esq., F.R.S. and L.S. By William Valentine, Esq., F.L.S. 



The author commences his letter by observing that subsequent ex- 

 amination of mosses leads him to concur in Mohl's views with regard 

 to the fourfold development of sporules in a mother-cell, a fact of 

 which he had expressed some doubt in a note appended to his paper 

 ' On the development of the Theca, and on the Sexes of Mosses,' in 

 ' Trans. Lin. Soc' xvii. 481. He says he now feels himself "bound 

 to confirm the accuracy of Mohl's observation in this respect : " and 

 then proceeds to give a detailed account of the structure of the theca, 

 and of the development and tetrahedral union of the sporules, as ob- 

 served by himself in CEdipodium GriflB.thianum, a moss found plenti- 

 fully on Snowdon, and examined in a recent state. 



From these observations it appears that like those of Pilularia, the 

 four sporules of CEdipodium are piled on each other in the mother- 

 cell, " so as to form a cone with a triangular base ; " like them, also, 

 the four are connected with each other, when young, by a " very mi- 

 nute stalk, situated at the junction of three radiating lines." The 

 author has " observed several instances in which the mother-cell con- 

 tained 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." 



The following observations on the analogy subsisting between the- 

 cae and anthers, and on that between sporules and pollen, which the 



