THE ALGJE OP GUERNSEY. 373 



fortune to discover four species which are entirely new to the 

 British flora. These are 



Streblonema Zanardinii, 



Polysiphonia opaca, 



Liebrnannia Leveillei and 



Lithophyllum expansum. 

 For the identification of these novelties, as well as for an 

 immense amount of help in the determination of critical and 

 puzzling forms, I am indebted to the kindness of Mr. E. M. 

 Holmes, F.L.S. 



A great deal, however, still remains to be done among 

 the seaweeds of Guernsey before anything approaching an 

 exhaustive list can be compiled. My own work has been 

 chiefly done at intervals during the summer and autumn 

 months, and consequently many winter and spring species 

 have escaped me. And then again only a portion of the coast 

 has been at all carefully investigated. The entire western 

 half of the island remains practically unexamined, that is to 

 say, the part lying to the westward of Cobo on the north and 

 Petit Bot Bay on the south, and also the Yale coast between 

 Grandes Bocques and Bordeaux. When it is borne in mind 

 that certain seaweeds are excessively local, confined some- 

 times to one small cove, or even to a single rockpool, it is very 

 clear that a great many additions are still to be made to the 

 present list by close and persistent research. Moreover, it is 

 well known that some species are very uncertain in their 

 appearance, occurring in abundance perhaps during one season, 

 and then disappearing for years. But one thing, however, 

 may be affirmed ; no more delightful and productive field for 

 the algologist is to be found on the British shores, than this 

 little rockbound island of Guernsey. 



And now a word with regard to the Fresh Water repre- 

 sentatives of the group. It is customary to treat separately 

 and keep in distinct divisions the alga3 growing in the sea, and 

 those inhabiting fresh water and damp ground. And although 

 this arrangement is a very convenient one, it should always 

 be distinctly remembered that it is purely artificial. No 

 natural line of demarcation exists between the two. Several 

 genera include both marine and fluviatile species, and in 

 brackish pools plants normally belonging to both divisions will 

 often be found growing together. 



That Guernsey is not particularly rich in these lowly 

 forms of plant life is not at all surprising when we call to 

 mind its physical features. And yet I confess to a general 

 sense of disappointment at the paucity of species occurring in 

 what are to all appearance promising habitats. 



