(166) 



ments not contracted, and articulations not inflated in the middle. 

 Substance somewhat flaccid, more or less adhering to paper. Colour, a 

 rather bright brownish red. Favellse "roundish ovate at the tips of 

 shortened plumules." Tetraspores ellij)tical on the upper edge and near 

 the tips of the plumules. 



This species, it will be seen, differs chiefly from the preceding by 

 its somewhat smaller size, brighter colour, and particularly by the form 

 of the pliunules, and theu' articulations. These, instead of being- 

 thickened upwards, are thickest at the base, and gradually taper 

 upwards to a point ; and the articulations, instead of being inflated in 

 the midcUe and contracted at the dissepiments, are nearly cylindrical, 

 the dissepiments not at all contracted. These characters, althoxigh not 

 very difiicult to recognise in practice, will, we fear, be generally con- 

 sidered somewhat unsatisfactory for specific distinction. The species, 

 however, has been very generally recognised by observers, and that in 

 several cases independently of each other, and it is pretty constant to 

 its characters. In habit it is almost identical with that of the pre- 

 ceding, and we find it often in collections under its name ; the place 

 of growth of both species is the same. We have not found it on the 

 east coast, but on the west it is not unfreqiient, as far north as the 

 Orkney Islands, but more abundant on the south-western shores. 



EXPLANATION OF PLATE CXXIL 



Fig. 1. — Callithamnion hrachiatum, natural size. 

 2. — Pinnre with tetraspores. 

 3. — Pinnule from same. 

 A. — PinnjB with favellse. All magnified. 



