(184) 



and closely adhering to the paper in diy 

 parent lake. 



lUg. 



Colour, a fine deep trans- 



With this beautiful species we are but very imperfectly acquainted, 

 having only seen some very imperfect specimens from the Continent, and 

 we have preferred giving the specific characters as given in Phycologia 

 Britamiica, to any we could form from fragmentary specimens. We 

 have not seen any native specimens, and in this country it appears to be 

 very rare, and, so far as we are aware, only found on the Irish shores. 



From G. Borreri, to which it seems most nearly allied, it differs chiefly 

 in having the branching more perfectly distichous, and the naked bases 

 of the pinnules interrupted by the solitary, spine-like, generally fertile 

 ramulus on the upper edge at the base, and in the tetraspores being 

 generally confined to these ramuli, or at most to a few of the lower 

 pinnulse. Its distribution along the Atlantic shores of the Continent, as 

 well as in the Mediterranean, would induce the hope that it may yet be 

 found on the south-west of Englaiid, and in the Channel Islands. 



CALLITHAMNION TRIPINNATUM. 



EXPLANATION OF DISSECTIONS. 



Fig. 1. 



-A plumule. 



-One of the smaller pinnse. 

 -A pinnule with tetraspores. 

 Phyc. Brit. 



All magnified. 



