the succeeding vertebræ, except only that the odontoid process is superadded to the centrum; and the bulging of the arch on each side behind the transverse process is well marked, and bears the inferior articular surface on its under side. On the other hand, the superior articular surface is placed partly on the odontoid process, but principally on the most anterior part of the arch, viz., that part which, in all the succeeding vertebræ, forms the posterior angle of the body (fig. 3). So also on the anterior extremity of the arch. are placed the articular surfaces (both superior and inferior) of the atlas (fig. 4); and also, in the dorsal region, the surfaces for the heads of the ribs. The occipital condyles are placed upon the most anterior parts of the arch of the occipital bone, and to a small extent upon the centrum. The foregoing examination of vertebral articulations leads us to observe, that, when surfaces for a synovial joint are present upon the body of a vertebra, however little of the body they may cover, they are never absent from those angles which are formed by the arches. The synovial articulations between the bodies of vertebræ in mammals are arranged in the following manner: In the dorsal region are the synovial capsules for the heads of the ribs, which always occupy the angles of the bodies, but are also, in many animals, united across the middle line between the intervertebral disc and the conjugal ligament; while in some cases, as in the horse and the sheep, a small line of cartilage is stretched along the superior margin of the posterior of the two vertebræ concerned in each joint. In the cervical region in the human subject, the minute joints described by Luschka,* are situated between those parts of the bodies which are formed by the arches. Lastly, in the atloaxoid and atlo-occipital articulations, the principal parts of the articular surfaces are placed upon those parts of the arches which correspond to the angles of the bodies of succeeding vertebræ, while the intervertebral discs have disappeared. I may here remark that, if the odontoid process be re* Luschka, Die Halbgelenke des Menschlichen Körpers, 1858, p. 71, and Tab. I., fig. 2. garded as the centrum of the atlas,—a view which seems to be supported by its very large comparative size in the young condition, long before the anterior tubercle of the atlas makes its appearance,—then we must recognise in the odontoid ligaments the terminal member of the series to which the transverse ligament of the atlas and the ligamenta conjugalia belong; and indeed the arrangement of their fibres, some of which are continuous from side to side, is favourable to this supposition, and reminds one of the ligamentum conjugale in the sheep. d Fig. 1. Atlas of a young Chelonia virgata-after Rathke. a, The arch b, Osseous centre of the tubercle. Fig. 2. Dorsal vertebra of a young seal, for comparison with the following figures: a, Oblique process. 6, Articular surface for head of rib. Fig. 3. Superior aspect of the axis of a human foetus. a, The centrum, b, Odontoid process. c, Superior articular surface. d, Bulging of the arch in the situation of the inferior articular surface. Fig. 4. Inferior aspect of the atlas of the same subject. a, Articular surface. Fig. 5. Cervical vertebra from the same subject. a, Oblique process. b. Part of the arch entering into the composition of the body of the vertebra. NOTE. Since writing the above, my attention has been called to Rathke's work, "Ueber die Entwickelung der Schildkröten," in which (page 77) the view that the odontoid process is the centrum of the atlas is strenuously urged, and strong evidence brought forward in its favour. See also Owen, "On the Homologies of the Vertebrate Skeleton," page 93. Rathke points out that the ligamentum suspensorium, which, in the birds and higher reptilia unites the odontoid process to the occipital condyle, is the serial representative of the intervertebral discs behind. He found that in most chelonians it consisted of true cartilage, and that in certain birds it was composed of fibro-cartilage. This view of the ligamentum suspensorium is quite consistent with the suggestion which I have offered, that the ligamenta alaria are homologous with the transverse liga ment. The large portion of the cup on the anterior aspect of the chelonian atlas, which is formed by the expanded inferior extremities of the arch, illustrates very well the unity of plan upon which the articular surfaces of the atlas are formed in animals having one occipital condyle, and those which have two. This will be seen by comparing the woodcuts above. When, in the human subject, a process of bone passes up from the arch of the atlas, to meet the superior articular surface, and convert the groove for the nerve and vertebral artery into a foramen, the process in question is a true oblique process. If, in addition, we were to imagine the tip of the transverse process thickened and projecting upwards to meet the superior articular surface, we should then have presented to us the condition of parts found in the pig and the sheep. IV. Ornithological Notes. By JOHN ALEXANDER SMITH, M.D. (Specimens exhibited.) (1.) Falco islandicus, (Lath). The Gyrfalcon. This specimen of Gyrfalcon was killed about the middle of last October by James Maclean, gamekeeper to Sir John Orde, on his property near Loch Maddy, in North Uist. The bird is probably a young male, and a very fine specimen of this extremely rare and occasional visitor, -no instance of its breeding in Scotland, he believed, was on record. It measured in length 22 inches; the wing, from flexure to point of primaries, 15 inches. The head white, with longitudinal stripes of brown; the upper parts of body brown, tinged with grey; the feathers partially edged and spotted on the margins with white. Below white, with longitudinal spots of brown; the flanks white, broadly dashed with brown. In the wings, the second primary is the longest, the first and third being nearly equal. Tail brown, barred with white, the white mottled with brown. Another specimen of this falcon was killed by Maclean during the autumn of the previous year; but unfortunately nothing but the head and wings were preserved. The bird was new to the keeper, being the first of the kind he had seen. (2.) Picus major. (Linn.) The Pied Woodpecker.-The Pied or Greater Spotted Woodpecker exhibited, was taken on Mr Trotter's property of The Bush, near Penicuik, on 7th November. Mr James Stewart, who shot the bird,was attracted, at about 100 yards distance, by the noise made from its tapping on the trunk of a large oak tree. The bird was an adult male, showing the crimson occiput. our permanent residents, but rare. It is one of Dr Smith brought under the notice of the Society in 1851, a specimen killed in the neighbourhood of Dryburgh Abbey. (3.) Lanius excubitor. (Linn.) The Great Grey Shrike. -Dr Smith noticed the capture of a Great Grey Shrike, on the 9th of November, in the vicinity of Dirleton, East Lothian. (4.) Perdrix cinerea. (Linn.) Common Partridge.—An accidental variety of the Common Partridge was also exhibited, showing pure white feathers in the scapulars, wings, and tail. V. A large Cup-shaped Sponge was exhibited by JOHN ALEXANDER SMITH, M.D. A very large and fine specimen of a Cup-shaped Sponge, Halichondria ventilabrum, attached by its base to a stone, was exhibited. It was sent from Shetland, where it had been dredged up from the sea bottom. The Sponge was sent for exhibition, at Dr Smith's request, by Mr James Carfrae, Princes Street, who was desired to make inquiries as to the exact locality where it had been discovered.* * This sponge has since been acquired for the Museum of Natural History, University. VOL. II. 2 G Wednesday, 26th December, 1861.-WILLIAM RHIND, Esq., President, in the Chair. The following gentlemen were elected the Office-bearers for the Session 1860-61: Presidents-Thomas Strethill Wright, M.D., Alexander Bryson, Esq., James M'Bain, M.D., R.N. Council-John Coldstream, M.D., Andrew Murray, Esq., John Cleland, M.D., William Rhind, Esq., David Page, Esq., William Turner, M.B., Esq. Secretary-John Alexander Smith, M.D. Assistant Secretary-James Boyd Davies, Esq. Honorary Librarian-Robert F. Logan, Esq. Library Committee-W. H. Lowe, M.D., John Anderson, Esq., John Livingston, Esq. Wednesday, 23d January, 1861.-ALEX. BRYSON, Esq., President, in the Chair. William Burns Thomson, Esq., surgeon, Superintendent of Medical Mission Dispensary, 39 Cowgate, was elected a non-resident member of the Society. The following donations to the library were laid on the table, and thanks were voted to the donors: 1. Biographical Sketch of the late William Oliphant, Esq., publisher, Edinburgh. From William Gibb, Esq. 2. Iagttagelser over Den Postpliocene Eller Glaciale Formation I En del Af Det Sydlige Norge. Af Profr. Dr M. Sars og Lector Th. Kjerulf. Christiania, 1860.—From the Royal University of Norway. 3. Jahrbuch der Kaiserlich-Koniglichen Geologischen Reichsanstalt, 1859. X. Jahrgang, No. 3, Juli, August, September. Wien.-From the Society. 4. The Quarterly Journal of the Geological Society. No. 58, May 1859, Vol. XV., Part 2.-From the Society. 5. Fragmenta Phytographia Australia. Nos. VIII, IX., X. With Plates. From Dr Ferdinand Mueller, Victoria, Australia. 6. Canadian Journal, Toronto. No. XXVI., for March, and No. XXX., November 1860.-From the Canadian Institute, Toronto. The Communications read were as follows: I. On Inflammation in Fishes. By ALEXANDER M'KENZIE About the year 1859, the attention of Scottish surgeons was drawn to some suggestions made many years before, by |