Marine Animals by means of Seaweeds. 421 
it very difficult to detect specimens drifting in the sea, unless 
there is an almost complete calm accompanied with bright 
sunshine. 
Numerous examples of single valves of Tapes pullastra, 
Ostrea edulis, fragments of Corallina, and stones of various 
sizes have frequently been observed drifting in the tideways 
attached to the roots of Chorda filum and various species of 
Fucus. 
Only two species of Nudibranchs have been secured on 
drift-weed. ‘Two specimens of Polycera quadrilineata were 
found early in July, and several examples of Acanthidoris 
pilosa were captured early during the following month on 
masses of Fucus serratus while travelling seawards. On a 
similar clump of weed a large coil of spawn, deposited by 
Aplysia hybrida, was once noticed. Microscopical examina- 
tion of these ova showed that segmentation was just com- 
pleted. 
The polychzete annelid, Spirorbis borealis, is very common 
on the fronds of Fucus se#ratus. It will be remembered that 
the embryos of this species are kept inside its tube until they 
are in an advanced condition and almost ready to lead an 
independent life. This fact doubtless greatly assists in the 
propagation of the species. Specimens of this annelid 
attached to the fronds of Fucus serratus can be secured in 
the tideways on almost any occasion. 
Very frequently, particularly during the months of June, 
July, and August, specimens of [dotea tricuspidata have been 
found holding fast to the fronds of Halidrys siliquosa. ‘These 
crustaceans are exceedingly difficult to detect, as they invari- 
ably adapt their colour to suit their surroundings, and also 
hold the stem of the drifting weed longitudinally. 
The undermentioned species of Hydroids have been 
observed on drift seaweed: Clava multicornis and Sertularia 
pumila occur in abundance on the fronds of Fucus versicu- 
losus and F’. serratus, and Aglaophenia pluma at times covers 
the fronds of Halidrys siliquosa. The following examples of 
Polyzoa will be sufficient for my present purpose :—Bicellarta 
ciliata and Mimosella gracilis are both to be secured in 
abundance on the fronds of Halidrys siliquosa. Membrani- 
pora pilosa, Flustra foliacea, and Valkeria uva have repeatedly 
been observed alive and in a healthy condition growing on 
detached portions of Hucus serratus gathered in the bay and 
harbour, The common anemone, Anthea cereus, is usually to 
be found adhering to rocks in pools of water between tide- 
marks; it also luxuriates on the fronds of Laminaria a few 
feet below low-water mark. In sheltered places in Falmouth 
harbour large areas exist covered with sea-grass (Zostera 
