Botanical Society of Edinburgh. 143 
The filaments are formed of a tubular horny thread, supporting on 
one side a broad membranous fringe. I could perceive no trace of 
vessels in this fringe, but it appeared to be covered by an epithelium 
(ciliated ?). 
The mouth is placed at the anterior and superior part of the ani- 
mal, between two thickish horizontal lips. The labial tentacles are 
two on each side, rather long, lanceolate, and slightly pectinated. The 
anus is placed posteriorly and superiorly between the gills, and just 
about the posterior adductor muscle. 
The so-called “foot” is composed of two portions, an upper and 
quadrilateral (properly the abdomen), and a lower pointed part (the 
true foot), the two being set at right angles to one another. 
The first portion is sharp-edged and slightly pectinated posteriorly, 
marked by a groove bounded by two folded lips anteriorly. The 
second portion is slightly pectinated along its lower edge, pointed 
anteriorly, prolonged behind into a curved process, where it joins the 
superior portion. 
Visceral mass.—The mouth opens by a very short cesophagus into 
a wide pyriform stomach, surrounded by a dark dendritic liver. The 
stomach narrows into a long intestine, which descends for the whole 
length of the abdomen, and forms one or two loops in the substance 
of the generative gland; then passes up again above the stomach, 
penetrates the heart, and passing between the two small lateral mus- 
cles of the foot, terminates in the anus. 
BOTANICAL SOCIETY OF EDINBURGH. 
December 13, 1849.—Dr. Lowe in the Chair. 
The following communications were read :— 
1. “Onthe Plants of the Valley of Fatana, Taheite,”’ by Archibald 
Sibbald, M.D., R.N. The author gave a list of the species observed 
by him in the Valley of Fatana, in Taheite, with their native names, 
and remarks on their properties, and the uses to which they are ap- 
plied by the inhabitants. The paper was accompanied by specimens 
of the “Tapa”’ cloth, and an account of the mode in which it is pre- 
pared from the bark of the bread-fruit-tree, Artocarpus incisa. 
Mr. M‘Nab exhibited a book containing specimens of native cloths 
collected during Captain Cook’s voyages among the South Sea Islands. 
2. “On some Scotch Freshwater Algz,”’ by Wyville T. C. Thom- 
son, Esq. The author laid before the Meeting specimens of fresh- 
water Algze, collected during the past summer chiefly in the west of 
Scotland. Of the genus Batrachospermum, specimens of B. atrum 
were exhibited, of a very large size, found in Ayrshire during the 
month of October. Mr. Thomson remarked, that the supposed 
rarity of this species probably originated in its being sought for at 
the wrong season ; he had found it sparingly during the early part of 
the summer attached to stones at the bottom of still, clear pools, the 
specimens being usually about an inch or an inch and a half high. 
When found in the end of autumn, however, the plants were free, 
floating on the surface of the water or attached to the ice. At this 
