chyma of the body supporting it are drawn out into a long thin process. When the animal issues from its tube, it protrudes its ciliary organ as a fleshy column, fringed on one side by a row of very long motionless cilia, but in an instant the column is twisted into a spiral, and the cilia are set in violent motion, urging currents of water towards the mouth. The marine species approaches in character, as to its rotatory organ, to C. Mulleri, while it inhabits a mucous tube like that of C. Mucicola.

6. Oxytricha longicaudata. (Pl. XIX. figs. 7, 8.)

This remarkable animal, resembling very much Oxytricha retractilis, described by Claparede and Lachmann, was found in great numbers with Chatospira maritima. The tail in this species is fully twice as long as that of Oxytricha retractilis, and is dragged after the swimming animal like a trailing rope, when suddenly the extremity of the tail is fixed by the long cilia at its extremity, and the Oxytricha, by violent contractions of its tail, jerks itself backwards and forwards in the most violent manner. The structure of tail, under an excellent power of eighty diameters, presents a peculiar striated and plaited appearance, like that of voluntary muscular fibre, but I could not make anything of it under higher powers.

Description of Plate XVII.

Figs. 7, 8.-Acharadria larynx.

Description of Plate XVIII.

Zooteirea religata, seen by black-ground illumination, and focussed for the centre of the "endosarc;" a, with palpocils extended and curved by an upward current of water; b, emerging from its cell; c, retracted within its cell.

Description of Plate XIX.

Fig. 1.-Zooteirea religata, with palpocils partially extended, and tubular contractile pedicle distended by water; a, ectosarc; b, endosarc; c, tube; d, muscular band; e, areolar fibres; f, gelatinous cell.

Fig. 2.-Young Freya producta building its tube.

Fig. 3.—Freya producta with lengthened tube; a, old mouth of tube; b, thickened part of body from which the tube is secreted.

Fig. 4-Freya obstetrica; a, nucleus.

Figs. 5, 6.-Freya stylifer, extended, and in its cell.
Fig. 7.-Oxytricha longicaudata, with tail extended.
Fig. 8.-

with tail contracted.

VI. On peculiar Hooked Spines on Ophiocoma bellis, with Observations on the Spines of other Ophiocomæ. (Plate XX.) By CHAS. WM. PEACH, Esq., Wick. (Specimens and drawings were exhibited.)

On the 26th January 1859 a paper of mine was read, giving an account of the discovery of hooked spines on Ophiocoma rosula, of which I had seen no notice in any work on British star-fishes. In April of the same year, when in London, I called at the Museum of Geology, Jermyn Street, and on mentioning this to Professor Huxley, he at once referred me to a work in which similar spines were figured from star-fishes found in the Mediterranean-viz. Müller and Troschel's "System der Asteriden, 1842." Two species are figured and described as having jaw-like hooked spinesone at Table IX., fig. 4,—Ophionyx armata,—another at Table X., figs. 1 and 6—Astrophyton verrucosum. I only mention this work, so that any one feeling an interest in the subject may know where to refer. On the 14th June 1861, having obtained a large mass of star-fishes from the stomach of a cod, I found that about a hundred were Ophiocoma bellis. After carefully washing them, I placed portions under the microscope, and found that the under sides of the rays were furnished with hooked spines, like those I had before found on Ophiocoma rosula. They are not quite so distinct, nor so constant in form, and do not extend so far on the rays towards the disk; for about the middle, they become more and more obscure, and before reaching it are straight, short spines. As well as the hooked-jaw like ones, the straight spines above these have hooked tips. Ophiocoma bellis is very abundant here, and is a favourite with cod-fish, as proved by the immense quantities found in their stomachs. Last night, in searching amongst my stores, I found enclosed in glass a specimen of Ophiocoma granulata, thus placed more than nine years ago; and, although pretty perfect, it was not in such a good state of preservation as I could have wished. Being the only one available, I was glad to have it. Although no hooked jaw like spines are to be found on the under side of it, a provision has been made for its wants, by furnishing large hooks to the lower straight spines. These

are most hooked towards the ends of the rays. There is however, a peculiar feature to be noticed in this species: although it has not the jaw-like spine, it is furnished with "two little obsolete or undeveloped spines." Ophiocoma rosula and Ophiocoma bellis have one only of these "obsolete spines"-valves I would rather call them-for an opening may be seen when these are raised, out of which the pinnated cirrhi are protruded. I regret exceedingly that I cannot find the drawings of Ophiocoma rosula where these cirrhi are shown, and which I sketched from a living specimen. I find in a specimen of Ophiocoma Ballii that the lowest spines on the under side of the rays are crowned with small hooks; and I have every reason to believe that most of the Ophiocoma are more or less provided with hooks, either on straight or jaw-like spines.

DESCRIPTION OF PLATE XX.

Fig. 1.-Part of a ray of Ophiocoma bellis, showing spines, valves, &c.
Figs. 2, 3, 4, 5, 6, 7, 8.—Spines from various parts of the ray.

Fig. 9.-Part of a ray of Ophiocoma granulata, showing spines, &c.

Fig. 10.-One of the uppermost spines.

Fig. 11.-Hooked spine from the under side of the tip of a ray.

VII. The Geology of Moffat, Dumfriesshire. By WILLIAM
CARRUTHERS, Esq., F.L.S.

Lithology.

I purpose in this paper describing the geological features of the district around Moffat, taking the village as my centre, and including all that lies within a radius of four or five miles. The district is situated in the centre of the immense Silurian tract of the south of Scotland; its predominant rocks consequently belong to the Silurian period. A red sandstone lying unconformable to them is the only other stratified rock. The superficial deposits are not numerous; they consist of boulder clay, gravel and sand, peat and shingle. A trap-dyke, which runs through the district a mile below Moffat in a south-east direction, is the only igneous rock with which I am acquainted.

VOL. II.

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