INTRODUCTION. 
5 
The tidal rocks, again, which are mostly covered by sea¬ 
weeds, present a varied and prolific site for many species. 
The rock-pools are both frequent and picturesque; and they 
possess many undisturbed stones, often of large size, the under 
surfaces of which are most favourable for the growth and 
shelter of numerous forms—though of course they cannot be 
compared in this respect with the littoral stones at Herm, which 
have a profusion of rare crabs, annelids, ormers and other 
mollusks, polyzoa, hydroids, and the yellow, red, purple, green, 
and white sponges. The rocks may conveniently be divided 
into the East and West Rocks, the former stretching from the 
pier to the east, the latter from the pier westwards. The rock- 
pools in these resemble miniature oceans of surpassing beauty. 
The borders of the clear basins are luxuriantly fringed with 
different kinds of seaweeds— Fucus serratus, Ilalidrys siliquosa , 
Fur cellar ia, and Chondrus , and the broad blades of Laminaria 
saccharina hang sombrely downwards and trail on the bottom. 
These sober tints are here and there relieved by the fine green 
tufts of CladopJiora and the broad Ulva , the dark red of Cera- 
mium rubrum, and the pinkish hues of Gorallina. The latter, 
in some of the clearest and finest pools, is not infested by the 
little white coils of Spirorbis , so that it is variegated only by 
its own whitish tips, which are in strong contrast in the quiet 
depths with the dull olive roots of the tangles. 
The pools are tenanted by representatives of all the animal 
subkingdoms; and many species are in profusion. Cotti , gun¬ 
nels, blennies, shannies, gobies, and sucking-fishes swim in 
the clear water or glide under the protecting seaweeds. 
Bunches of Furcellaria and Fuci afford a site for Eolidce ; and 
Hyas , Car emus, and Pagurus nestle in their shade or peram¬ 
bulate the bottom. In some pools beyond the Maiden rock 
Palcemon squilla abounds, darting hither and thither with 
great velocity or poising its long antennas over the seaweeds 
in graceful curves. Minute crustaceans and mollusks people 
the laminarian blades, while the roots give shelter to many of 
the forms previously mentioned. The larger mollusks (. Buc - 
cinum , Purpura , and Trochus ) crawl on the same leaves, or 
adhere in the society of limpets to the margins of stones. 
The under surface of the latter reveals a varied fauna. It is 
