THE GENERA OF MOSSES. 
467 
to all the plants we have brought together, we have been 
obliged to reject both, although, from respect to Mr Brown, 
and friendship for our correspondent Dr Hornschuch, we 
would gladly have avoided it, if possible. Had not the 
name Orthodon been preoccupied, it would have been pre- 
cisely that we should have taken for the present genus ; 
which we have denominated Dissodon^ a word at least ex- 
pressing a character common to all the species. The first 
known of our species was described and figured by Hed- 
wiG, and about the same time discovered in this country by 
Dickson on the Scottish alps. Dickson seems to have dis- 
covered the next, and published it as a S'plachnmn ; but 
SwARTz, almost immediately following, described it as a 
Weissia, the generic name of which it has retained ever 
since, till Brown gave it that of Cyrtodon, Of this plant, 
we may here remark, that, from the imperfection of the 
specimens existing in herbaria, no correct figure had been 
given till the year 1824, when both Dr Hooker and Dr 
Greville published ample analyses of the different parts. 
The geminated structure of each tooth was observed some 
years ago by Mr Arnott, in specimens procured from the 
Reverend Mr Macritchie of Climie, and urged with se- 
veral muscologists as a proof how incorrectly it had been 
allowed to remain in the genus Weissia. Mr Brown, how- 
ever, has the first claim for the publication of this structure. 
To Dr Hornschuch we freely expressed our opinion that 
his Systylmm could not be separated as a genus from the 
same plant. Along with additional specimens for examina- 
tion, he obliged us, in return, with the following remarks : 
— " Ich night glaube dass es mit Weissia Splachnoides in 
ein genus vereinigt werden kann, da der Bau der Taehne 
gar zu bedeuteotend abweicht, wie Ihnen die Untersuchung 
zeigen wird, audi ist die Verwachsung des operculi mit der 
Columella so standhaft und ausgezeichnet dass sie nach 
Gg2 
