382 musci. 



In Trematadon longicolljs, I had opportunities of ascer- 

 taining the correctness of the observations of Mr. Valentine 

 on the development of the setae. With those observations 

 I am only however partially acquainted. The old and incor- 

 rect ideafl appear nevertheless to still prevail, and are admit- 

 ted into the second edition of Mr. Lindley's Introduction to 

 Botany. The explanations too adopted in this excellent book 

 as to the difference between a mitriforra and dimidiate calyp- 

 tra, and an outer and inner peristome, are likewise particular- 

 ly erroneous. 



With regard to the development of the setae of Musci, I 

 know of no analogous instances, excepting Jungermannia, 

 which is undoubtedly vaginulate. The changes subsequent to 

 fecundation are, in these, much more complicated than in 

 Phaenogamous plants, in which they are limitted almost uni- 

 versally to the maturation of a pre-existing ovule ; whereas 

 in these, they are extended not only to the development of 

 the sporula, but to the generally highly complex apparatus 

 in which these are contained. 



I am not aware whether any one has explained the opposi- 

 tion of the teeth of the peristome in Funaria. But looking 

 at the situation of the carinas or plicae that exist in the mem- 

 brane of the inner peristome, which are invariably alternate 

 with the teeth of the outer peristome, and at the allied genus 

 Bartramia, it is evident, that the anomaly arises from the co- 

 hesion of the component parts of different processes, each of 

 which thus becomes strictly compound. 



I have approximated Pterogonium to Neckera, on account 

 of its habit, and the laterality of its setae : in its capsule and 

 peristome it approaches nearly to some Weissiae. 



Daltonia 1 have adopted in the sense of Bridel. Neckera 

 heteromalla, which Dr. Hooker refers to Daltonia, agrees en- 

 tirely with Neekera in its inner peristome, and must, if at- 

 tention be paid to its mitriform calyptrae, be referred to Poly- 

 trichum of Bridel, or Daltonia of Mr. Arnott ? 1 have no 

 opportunity of examining Anomodon, which can only differ in 



