Reptilia et Aves.—Our two greatest Anatomists of the past century, Owen and Huxley, both contributed to this section of our palaelig;ozoological record. Owen (in 1865) described some remains of a small air-breathing vertebrate, Anthrakerpeton crassosteum, from the Coal-shales of Glamorganshire, corresponding with those described by Dawson from the Coal-measures of Nova Scotia; and in 1870 he noticed some remains of Plesiosaurus Hoodii (Owen) from New Zealand, possibly of Triaasic age.

The skull of one species (A. Zitteli) of this remarkable ungulate has already been figured by Mr. Beadnell, and also in this Magazine (December, 1903), where its general form is well shown. Details of the structure of the skull and skeleton will be given in the monograph, so that only a few of the more important characters need be referred to here.

The pedunculate occipital condyles are very large and prominent; the occipital surface slopes strongly forwards and is bordered by a massive lambdoidal ridge, which on either side (in old animals at least) rises into a prominent backwardly directed boss of bone, almost like a blunt horn. The parietal region of the cranial roof is flat and is at right angles to the side walls of the skull, being sharply marked off from them by well-defined ridges, which form the upper limits of the temporal fossæ. The suture between the parietals is obliterated in the youngest skull examined. The pair of small posterior horns over the orbits are borne exclusively by the frontals, while the great anterior pair seem to be formed entirely by the enormously developed nasals.

The old question of the proper interpretation of these names, which was raised by Professors Nikitin and Pavlov, after their visit to this country for the Geological Congress in 1888 to whom no reply was made, for their conclusions could scarcely be denied, has been raised again by Miss Healy in a communication to the Quart. Journ. Geol. Soc., Feb. 1904. As these conclusions do not appear to be well known, it may be as well to quote them. Nikitin says: “Having found in the British Museum the original of Am. biplex, Sow. (tab. 293, fig. 1), I assured myself that that original presented absolutely the Oxfordian form of Perisphinctes of the group of P. plieatilis, by the character of its numerous straight rounded ribs, by the mode of enrolment, by the constriction of its perfectly visible whorls, and lastly by the matrix; it showed no resemblance to the Kimmeridgian and Portlandian forms described in France and England under this name… Mr. Loriol had not seen the original of Sowerby… but having received from England, under the name of A. biplex, Sow., the Portlandian forms, he was justified in giving this name to the same form from Boulogne. On studying the English Kimmeridgian forms placed in the museums of England under the name of A. biplex I found amongst them the typical form of A. Pallasi, D'Orb.’

Mr. Alexander Somervail has been so good as to send me lately a paper read by him before Section C of the British Association at Southport, September, 1903, and printed in the Geological Magazine, Dec. IV, Vol. X, No. 472, October, 1903. The paper contains certain criticisms on the published work of Professor Hull, F.R.S., and myself among the Bed Rocks of the South Devon coast, with especial reference to “ the Base of the Keuper iu South Devon.” I desire to reply here to Mr. Somervail, and in so doing shall have to refer frequently to the three papers of my own published in the Quarterly Journal of the Geological Society in the years 1888, 1892, 1893, and to the paper by Professor Hull in the same Journal in the year 1892. For the sake of convenience and brevity I will refer to these papers by certain letters, as below.

In the Summer of 1902 I commenced an exploration of the chalk-pits on the eastern border of the Lincolnshire Wolds, starting at Louth and working northward. Mr. W. Hill had previously visited this locality, and had proved the existence of the zone of Holaster planus at Boswell, three miles north-west of Louth, and also at Kirmington, much farther north. Mr. Jukes - Browne suggested to me that I should try and obtain fossils from the intermediate pits, and thus extend the work commenced by Mr. Hill. As the result of visits to about thirty pits, ranging from near Louth to Barrow-on-Humber, I have obtained further evidence of the zone of Holnster planus, and also some indications of the zone of Mieraster enrtestudinarium.