INTRODUCTION. 
XV 
surface, nearly a quarter of a mile in extent, you have but to turn to the right hand, where some 
large blocks of stone rise up in a sloping position, and underneath the slope you may gather 
handfuls of Catenella opuntia (Fig. 204), as you stand; while in the adjoining pools the 
grass-green Enteroinorplias (Plates LXX. and LXXI.) come, obedient to the zone law which 
gives them the upper level as their peculiar habitat. 
Nor are the intermediate levels — hanging-gardens, as it were, of the sea — between high and 
low* water mark, difficult to be got at, if only you have remembered to put on a strong pair of 
gloves, and will condescend to use hands as well as feet to ensure your safety. But by this 
time there is no doubt the disciple will have become as reasonable as nature intended her to 
be — will have realised the wisdom of wearing woollen petticoats among wet rocks, and thick 
boots when she has to walk over beds of Fucus vesiculosus (Fig. 10), and Himanthalia lorea 
(Fig. 16). 
As to the hanging-gardens themselves, they afford a good opportunity for a minute study 
of zone vegetation ; but this is a subject for the more advanced student, who can open Dr. 
Harvey’s works and follow him in this and other interesting discussions. And now, even 
among the pools, the old rule holds good — the prettiest things are not to be got at without 
trouble. The disciple will have to kneel or sit down on the rock and lift up the coarser plants 
which often fringe the edge of such places, and look underneath for delicate Corallinas (Plates 
XXXIII., XXXIV.), Polysiphonias (Plate XXVI., &c.), and other scarcer things, or she will 
come away knowing nothing of the pools at all. But, alas ! here is no space for fully pursuing 
this subject. Only remember that the perpendicular faces of rocks have their growths as 
well as the pools, and that a good collector must, like a good nurse, keep her eyes open all 
round her ; while, on the other hand, the injunction cannot be enforced too strongly, that she 
had better go home hurriedly than overload her basket and spoil everything it contains. 
It will be understood, of course, that what has now been said of Filey Bridge applies to 
other rocky shores, although the zones of growth are more easily observed there than elsewhere. 
But they exist everywhere — everywhere grass-green is the earliest life in the first vegetation- 
line ; mixed gradually with some of the more delicate olive plants, Ectocarpus (Plates XIX. &c.), 
Asperococcus (Fig. 46), &c. Everywhere the Laminarias^ and the rarer red plants, are to be found 
only at low-water level, but the popping sea-weeds, the End (Plates III. and IV.), throughout 
the whole range, save only the extreme last. Exceptions excepted, an examination of any shore 
will prove these statements correct, and enable the collector to judge whereabout she is, 
algologically speaking, on even a perfectly strange coast, and to regulate what she looks for, 
accordingly. 
Another subject of interest to the algologist is the influence of climate on the growth of 
special plants, for this may often decide her in a choice of stations. Sea-water varies very 
much both in temperature and saltness, and it would be as unreasonable to look for Devonshire 
myrtles in Yorkshire gardens as for Devonshire algae in its waters. But here latitude is not 
everything. Douglas Bay, in the Isle of Man, is in nearly the same latitude as Filey, yet both 
the land and sea vegetation are very different ; and if it be asked why, no reason can be assigned 
but Gulf-stream influence. The point is open to discussion and objection, perhaps ; and there is 
a theory (with a diagram in its favour !) of a current which diverts the Gulf-stream from going 
further east than the Scilly Isles, and prevents its going up the Irish Channel at all, while it 
allows its influence on the west coast of Ireland. But if this be so, how is it that the blue 
