(178) 



ill the Hookerian herbarium, and oiir figures and description have been 

 mostly drawn from the Pltycologia Britannica, where the species or 

 form is carefully delineated. 



With the habit of G. corymhosxim it is described as having the- micro- 

 scopical characters of G. Borreri, the constricted joints of the pinnae 

 being very characteristic of the species. 



Its title to specific distinction seems fully as well founded as its right 

 to be considered a native of Britain, as no subsequent observer has ever 

 met with it, but whether an accidental form, or a stray waif from some 

 unexplored shore, cannot at present perhaps be determined. 



CALLTTHAMNION FASCICULATUM. 



EXPLANATION OF DISSECTIONS. 



Fig. 1. — Upper pinnse. 



2. — Pinnule with tetraspore. 



3. — Tetraspore from same. 



4. — Portion of stem. All magnified. 



