the Development of the Theca, and on the Sexes of Mosses. 503 
thecium of an anther, that in Jungermannia multifida 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 cavities 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 knowledge, of organized secretions in the cavities of simple cellules. 
Although the tetrahedral union of both sporules and pollen is almost always 
dissolved at an early period, yet in some instances, as in GZdipodium 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“. 
Then to apply, as it were, the precision of a chemical test, if sulphuric acid 
be applied to the sporules, the same phenomena occur as when it is applied to 
pollen. The effects of this test vary according to the nature of the contents 
of the sporule and the manner of its application, which must be carefully 
regulated to ensure a satisfactory result. If the sporules of Gymnostomum 
truncatulum, the contents of which are almost entirely fluid (Tas. XXXV. 
fig. 1.), be submitted to its action, they will burst, and a portion of the fluid 
will be discharged in various-sized globules (Tas. XXXV. fig. 2.). No pre- 
caution that I know of will ensure a different result in this species; but if 
sporules whose contents are chiefly granular, such as those of Leskea sericea, 
Tortula ruralis var. levipila, or Tortula rigida, be submitted to the action of 
the acid, which must be added to the water very cautiously and gradually, 
* I am aware that the sporules of Anthoceros punctatus are described by Hooker as being attached 
by a stalk to a central columella; and also, that Dr. Lindley has described the sporules of Andrea as 
being attached to the columella. Dr. Lindley also describes from Brongniart and Bauer the sporules 
of Salvinia and Azolla as stalked. In the case of Andrea he is certainly incorrect; and it is quite 
evident, from the account he has given of the latter plants, that their structure is involved in much 
obscurity. If it should be decided that these bodies are really attached by a stalk to a placenta, I 
should be inclined to suspect that they were not mere sporules, for it seems improbable that bodies, 
developed as sporules are in the cavities of cellules, should be attached by a stalk. May not what is 
called the theca be an inyolucrum, and the supposed sporules, each of which in Anthoceros is described 
as being compounded of three or four smaller bodies, be thecæ, each containing either , single union 
of four sporules, like Lycopodium selaginoides, or only one sporule, the rest being abortive, like Pilu- 
laria? 
