314 Transactions of tJie [Sess. 



familiar Acorn-shells, their crusted surfaces suggesting some vio- 

 lent eruptive disorder.^ 



The only Sponge noticed was Halichondria silicea, and of this a 

 few good specimens were got. A transverse section through one of 

 the exhalant apertures, with the rod-shaped spicules in situ, is shown 

 under the microscope. The Common Sea- Anemone or "Beadlet" 

 (Actinia mesemhryanthemum) was seen in the rock-pools. Of the 

 Annelids, there were observed Serpula vermicularis and Spirorbis 

 communis. The calcareous tube of the Serpula is fixed by the 

 apex to rocks or stones, while that of Spirorbis adheres by the 

 side to Fuci and oxher Seaweeds. Spirorbis was common : minute 

 forms of the tube make a very good slide for the microscope, 

 mounted as an opaque object. The Hydroids found were Obelia 

 geniculata and Sertularia pumila ; while the representatives of the 

 Polyzoa were Flustra foliacea and Membranipora membranacea. 

 These Zoophytes are familiar to most sea-side visitors, and are well 

 worth examination, especially in the living state. The Polyzoa are 

 a distinct advance on the Hydroida, inasmuch as they possess a 

 nervous system, which is wholly wanting in the latter. Obelia 

 geniculata is shown under the microscope by Mr Allan, with the 

 polypes in their cells or polypidoms. In order to procure this 

 object, the Zoophyte must be got in the living condition, and put 

 into a shallow vessel with sea-water. On pouring in a few drops of 

 spirit, the Polypes may be seen, by the aid of a hand-magnifier, in 

 a very active, not to say hilarious condition ; then suddenly com- 

 ing to a dead stop — killed off by alcoholic excess ! In the early 

 days of science these colonies of living beings, as well as Sertulari- 

 ans. Sea- Anemones, and similar forms, were classed amongst plants. 

 A square inch of Flustra foliacea, with its cells on both upper and 

 under surfaces, has been calculated to contain 1800 cells in all, 

 housing as many zooids. The specimens found on the beach 

 are always empty, and living forms must be dredged for. The 

 only two Star-fishes noticed were the common "Five-fingers" 

 {Asterias rubens) and the Sun-star (Solaster papposa). 



The Seaweeds fall now to be shortly mentioned. Of Fuci, the 

 four common forms were observed, all within a few yards — viz., 

 the Channelled Wrack [Fucus canaliculatus), the Knobbed Wrack 

 [F. nodosus), the Bladder Wrack [F. vesiculosus), and the Saw-shaped 

 Wrack [F. serratus). There were found, besides, the following : 

 Cladophora rupestris, Porphyra vulgaris, Ulva latissima and U. 

 linza, Halidrys siliquosa (in large quantities), Laminaria digitata, 

 Callithamnion polyspermum, Ceramium rubrum and C, acantho- 



1 An interesting note on the life-history of the Acorn-shell, with an illus- 

 tration, will be found in the ' Journal of Microscopy and Natural Science ' 

 for January 1886 — art. " Half-an-hour at the Microscope with Mr Tuflfen West, 

 F.L.S., F.R.M.S., &c." 



