214 Bibliograj)hical Notices. 



localities noted for F. Mackayi, an equally anomalous state of that 

 plant (at least, as we considered), when it appeared growing in 

 dense round balls of various size, but generally such as could be 

 spanned by the hands — the fronds were extremely narrow, vesicles 

 generally, and receptacles entirely wanting. 



At p. 44 (Introduction) it is remarked, under the head of " uses" of 

 Algse, that — " On many of our coasts, as along the west coast of Ire- 

 land, the poorer classes are almost entirely dependent for the culti- 

 vation of their potatoes on the manure afforded by their rocky shores 

 and frequent gales of wind." Of this we had a notable example 

 when at the town of Gal way some years ago. Turf-boats were dis- 

 charging their cargoes of sea- weed (Laminarieee) at the quay ; and on 

 inquiring whence it was brought, we learned, from Slyne Head, a 

 place distant between fifty and sixty miles, and that some of the pur- 

 chasers were, for the purpose of manure, about to convey it inland 

 thirty miles ! 



At p. 36 the author observes, with reference to a passage extracted 

 from the 'Algae Britannicae ' — " Several of these [species] , it is worthy 

 of remarking, which are in England confined to the coasts of Devon 

 and Cornwall, are found in Ireland along the shores of Clare and 

 Galway, where the Land Flora, it will be remembered, contains se- 

 veral species otherwise peculiar to the South of Europe." There is, 

 however, this important difference to be noted ; that, while the Land 

 Flora of the west of Ireland produces a few of the south European 

 species which are not found elsewhere in the British Islands, and are 

 their most northern stations, the Marine Flora has not presented us 

 with any one of the southern plants which are not found upon other 

 parts of the British shores. Mr. Harvey is silent upon one point which 

 we could have wished he had adverted to, namely, the causes of the 

 comparatively gigantic size that species attain in particular localities. 

 At p. 41 it is remarked that — " The Delesserice appear in greatest 

 perfection about 52° and 53°, those from the north of Ireland being 

 much larger than individuals of the same species from the southern 

 coasts of England." And again — " The Nitophylla are also chiefly 

 northern, six being found in the Atlantic basin, and in greatest per- 

 fection on the north coast of Ireland." Now we cannot believe (and 

 perhaps the author does not intend that we should) that the mere 

 difference in latitude between the south of England and north of 

 Ireland, or more strictly speaking, the county of Antrim, can so 

 affect the size of these plants. We are instead rather disposed to 

 attribute the magnitude which they attain in the latter locality, at 

 least in part, to the limestone or chalk on which they grow, corrobo- 

 rative of which it may be mentioned, that on the different geological 

 formation of the neighbouring coast of Down, the same species do 

 not exceed one-third of the size. We have remarked too, though in 

 a less degree, a difference of the same kind between the northern 

 and southern shores of the Isle of Wight, the chalk of the latter pro- 

 ducing examples of the same species incomparably finer and larger 

 than the different formation of the other portion. The influence 

 of different rocks upon Algae, as affecting their distribution, growth, 



