CINCL1D0TUS. 225 



C. riparius, with which it has been often united, but the seta in that plant is shorter, 

 and thicker, the leaves are less twisted, indeed almost unaltered and appressed when 

 dry ; and under the microscope the plane margins and smooth cells easily distinguish 

 it. There is no doubt as to the right to specific rank of the present moss, but it is 

 not so clear whether it should be placed under Tortula or Cinclidotus, between which 

 two genera it undoubtedly forms a connecting link. The structure of the peristome is 

 that of Cinclidotus, and the slight twisting of the teeth cannot be held of importance, 

 especially under the system of grouping the species which is here adopted, even 

 were it peculiar to this species and not common to the others of the genus. 



2. Cinclidotus riparius Arnott (Gymnostomum riparium 



Host) (Tab. XXXII. G.). 

 Resembling the last species, but aquatic rather than 

 terrestrial ; stems usually longer than in that, but shorter than in 

 C. fontinaloides , variously branched. Leaves oblong-Ungulate , 

 obtuse and usually mucronate with the excurrent nerve; or widely 

 acute and apiculate, about equalling the last in size, less twisted 

 when dry, usually appressed and flexuose, but not crisped nor 

 much twisted ; margin thickened, but less abruptly than in C. 

 Brebissoni, and not recurved; nerve more or less shortly 

 excurrent or ceasing just below the apex; areolation resembling 

 that of the last but quite smooth, the walls not much incrassate, 

 the basal usually shorter and less pellucid. Seta from the apex 

 of the stem or branches, short, i-2}i lines long, very thick ; 

 capsule broadly oblong, slightly curved, lid stout, acutely conical- 

 rostrate, curved; peristome yellowish, lightly papillose. 



Hab. Stones in streams. Very rare. R. Fergus, Ennis ; R. Teme, Ludlow. 

 Both sterile. Fr. summer. 



I have not seen specimens from the Irish locality ; I have examined specimens 

 gathered by Mr. Weyman in the R. Teme, and I feel considerable doubt whether 

 this is not a form of the next species, with shorter, rather broader leaves than usual, 

 and I find that Mr. Bagnall, to whom the English specimens were first submitted, is 

 now inclined towards the same view. The cells in C. riparius are quite smooth, 

 while those of the plant in question are, frequently at least, distinctly though shortly 

 papillose, exactly as in C. fontinaloides ; and the upper cells have the walls somewhat 

 incrassate as in that species, although it may be doubted whether this is, in the case 

 of the two species in question, a safe distinction. Taking into account the fact that 

 C. fontinaloides is a variable moss, and sometimes at least approaches very near to 

 the habit and structure of Mr. Weyman's plant, I think it is much more probable 

 that the latter belongs to that species, rather than to C. riparius. 



The seta in this species sometimes springs from a very short lateral branch, in 

 which case the plant is cladocarpous ; this occurs on the same tuft with the fruit in 

 the ordinary position, and shows the slight value to be attributed to this character. 



3. Cinclidotus fontinaloides P. Beauv. (Hypnum fontina- 



loides Lamarck) (Tab. XXXII. H.). 



Aquatic , stems long and flexuose , 2-8 inches long, in large 

 dense masses of a dull green or more frequently dark, almost black 

 colour, with short lateral branches; the lower leaves usually 

 P 



