478 Mr. VayENTINE on the Development of the Theca, 
in every esséntial particular. In support of an opinion so opposite to any 
hitherto proposed, I offer the following evidence*. 
The analogy of the development of, the sporules to that of e is very 
striking even to a superficial observer, and has not escaped the notice of 
botanists. A section of the anther of the common garden variety of Primula 
vulgaris, taken from a bud when about the size of a small pin's head, exhibits 
a structure wbich may be compared to a section of the theca of Polytrichum. 
In the former we find an axis of dense tissue (the connectivum) surrounded 
by the cuticle. "This axis is not central, but placed nearer to the cuticle, on 
the back of the anther, and may be considered as the columella; whilst the 
cuticle will represent the theca. A separation of the tissue gradually takes 
place, in four distinct points, nearly at equal distances from the axis. As the 
axis is not centrical, these points lie towards the front of the anther. Between 
each of these points the cuticle is furrowed longitudinally, so that the section 
has somewhat of a quadrangular figure. The theca of Polytrichum merely 
differs from this in having a complete separation of its tissue all round the 
axis instead of in four points only. The spaces caused by the separation (not 
dissolution) of the tissue, gradually enlarging, form the cells of the anther, in 
which the viscid secretion takes place. This secretion is afterwards converted 
into pollen, in a manner similar to that in which the sporules are formed. 
When the anther is nearly ripe, a still further separation of the tissue takes 
place, and the four cells become two. When perfectly mature, these cells 
* Since this paper was read, Mr. Brown has called my attention to a memoir by Professor Hugo 
Mohl (see Flora, No. 5, February 1833, p. 65, et segq.), in which the same views are advanced and 
supported at considerable length. 
I may also mention that on the second evening of the reading of this paper Professor Agardh of Lund, 
who happened to be present, informed me that he had maintained a similar view to the one above as to 
the nature of the sporules of the Alge, in a work which he had published, but which had not found its 
way into this country. [The work here alluded to is probably the second volume of the Lehrbuch der 
Botanik, of which a German translation appeared at Greifswald in 1832.] 
I am aware that Mons. Palisot de Beauvois endeavoured to prove that the sporules were mur. 
He maintained that the sporules impregnated the seed (which he fancied he had discovered), like the 
pollen of Phzenogamous plants;—a view the very opposite to the one proposed in this paper. 
Mr. Brown has long since (Linn. Trans. x. p. 314.) pointed out the error of M. de Beauvois, 
