601 
of Edinburgh^ Session 1865 - 66 . 
maddy the blades of this sea-weed are covered with a flocculent, 
muddy deposit, that appears to be favourable to Ascidian existence ; 
while at Paible they are fresh and clean, there being naught, 
indeed, but pure sand to deposit on them. 
The occurrence of inland seas affords an interesting variety in 
examining marine life. The most abundant animal species in 
these is Littorina tenehrosa^ which clothes the branches of the fuci 
with its myriad examples, and abounds under stones ; while swarms 
of the young of Rissoa striata and R. ulvce speckle the green 
Cladophora. The common mussel clings by its byssus to the fuci 
and stones ; but no large example was seen in such localities, either 
living or dead. The hand-net showed that Mysis chamoeleon and 
Idotea tricuspdata found amongst the sea-weed thickets both food 
and shelter; and the ubiquitous Gammarus locusta, and other 
sessile-eyed crustaceans, lurked under the stones in thousands, as 
well as sported in the water. Carcinus mcenas^ as fierce and wary 
as when in purer water, was common. Under the stones were 
numerous groups of the little Planaria ulvce. The sole representa- 
tive of the swimming jellies was a small medusa, with four lilac 
loops, like M. aurita. Of fishes there were grilse, trout, young- 
gobies, and rough-tailed sticklebacks. It was strange to find, 
within forty yards of such an inland sea, a true boggy, fresh-water 
lake, where we had the bold contrast of the white water-lily, car- 
damine, sparganium, horse-tails, and confervse, holding the place 
of the neighbouring fuci, and marine algae. Instead of the marine 
fauna before-mentioned, glistening beetles skimmed the surface, 
water-boatmen, dytisci and cyprides the depths, pond snails, 
cyclades, and leeches, climbed the water plants, and annelids and 
larvae crawled in the brown peaty mud at the bottom. 
Of the Coelenterata, nine were got within tide-marks, the most 
abundant being Sertularia pumila. Garyophyllia Smithii swarms 
at the verge of low water on the eastern side of the island, being- 
attached to rather muddy stones that lie piled over each other, so 
as to form small caverns, in which the corals hang, grow upright, 
or project horizontally ; they feed voraciously on the salpae. 
Amongst the anemones Anthea cereus attracts most notice from its 
curious arborescent habits on the fuci and laminariae of the creeks 
at low water. 
