Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/594

 3. Note on a Fragment of a Teleosaurian Snout from Kimmeridge Bat, Dorset. By J. W. Hulke, Esq., F.R.S., F.G.S.

[Plate XVIII.]

This piece of a Teleosaurian snout, which fell last winter from the cliff in Kimmeridge Bay, and was lately entrusted to me by J. C. Mansel, Esq., F.G.S., seems to me worthy of a short notice, as it is the first indication of this genus which, within Mr. Mansel's knowledge, has been discovered at Kimmeridge ; and I do not find in the British Museum any Teleosaurian fossils from this locality, nor are any mentioned in Mr. Seeley's recent catalogue of the fossil Reptilia in the Woodwardian Museum, although in both these collections there are Teleosaurian remains from other Kimmeridge-clay localities.

The fragment, 17 inches long, represents a very long and slender snout tapering gradually and slightly (its breadth decreases only 0.5 in. through a distance of 15.5 in.) to behind the external nostril, where the praemaxillae suddenly and largely expand. The nostril, wholly inclosed in these bones, is dilated, strictly terminal, and directed obliquely forwards ; its lower margin is interrupted by a prominent median tubercle formed of the swollen praemaxillary suture ; and a shallow convex lobe projects from the middle of the upper margin. The praemaxillae ascend 2.5 in. above the nostril, and end in an acute point, the maxillae composing all the remainder of the fragment. The upper surface of the snout is convex transversely, more so in front than posteriorly, where it becomes depressed ; but its transverse section nowhere approaches the semi- circular form of the stouter-snouted Steneosaurus Manselii, which I described last session. The lateral margins are slightly crenated by the prominent alveoli of the sixteen foremost maxillary teeth, the openings of which slant outwards and downwards, while the hinder ones look directly downwards. The palatal surface between the alveoli is convex transversely in front, and it becomes gradually flatter posteriorly. Throughout its whole length it descends below the level of the alveoli. No trace of the front ends of the palate- bones are discernible.

Most of the teeth have fallen out ; but a few, broken short off, remain in the sockets. The transverse section of the best-preserved of these teeth, at the neck, is nearly circular. Each praemaxilla contains five alveoli ; judged of by the size of these, the third and fourth teeth were larger than the others, and the first and fifth were the smallest. Each maxilla in the space of 15-5 in. has a series of twenty-five alveoli, of which the three front ones are smaller than the others.

The dilatation of the terminal nostril is much greater than in any other Teleosaurus known to me. I believe the fossil represents a new species, and I propose for it the specific designation megarhinus.

EXPLANATION OF PLATE XVIII.

Fig. 1. Snout of Teleosaurus megarhinus from Kimmeridge, seen from beneath, reduced.

2. The same, from above.

3. The same, from the left side.