[666] Hence the generic name, Dicynodon: from δις (twice), and κυνὁδονς (canine tooth).

[667] Prof. Owen’s Memoir on the Dicynodon, Geol. Trans. 2d ser. vol. vii. pp. 59, et seq.; and plates iii. to vi.

The fossils under consideration were exhumed some years since by Mr. Andrew Geddes Bain, from the intensely hard argillo-calcareous nodules of the sandstone strata which range over an immense tract of country beyond the mountains north of Capetown,[668] The extensive series of these and other fossils from South Africa, collected by the indefatigable labour of Mr. Bain, have lately been deposited in the British Museum; but the specimens described and figured in Prof. Owen’s Memoir, above alluded to, are nearly all that have as yet been successfully worked out from the exceedingly hard matrix in which the bones are imbedded. These consist of crania and jaws, referable to four species.[669]

[668] For a notice of the geological structure of this region, see Mr. Bain’s paper in Geol. Trans. 2d ser. vol. vii. pp. 53, &c.; and the abstract of a later Memoir by Mr. Bain, in the Literary Gazette, Dec. 18, 1852 (No. 1874).

[669] Namely, Dicynodon lacerticeps (lizard-head), D. testudiceps (turtle-bead), and D. strigiceps (owl-head), the trivial names of which have reference to the general form of the head; and D. Bainii, the largest, but unfortunately as yet the least known species, which takes the name of the intelligent and energetic discoverer and collector of the whole.

Lign. 232.

Lign. 233.

Lign. 232 and Lign. 233. Dicynodon lacerticeps. (Owen.)
South Africa.
(See Geol. Trans. 2d ser. vol. vii. pl. iii.)
The letters of reference correspond in the two figures.
Lign. 232. Side view of the Cranium and Lower Jaw: 1/3 nat. size.
Lign. 233. Upper aspect of the Cranium: 1/3 nat. size.

Cranium and Upper Jaw.
a, a.Intermaxillary bone.
b, b.Nasal.
c, c.Frontal.
d, d.Maxillary.
e, e.Prefrontal.
f, f.Lachrymal.
g, g.Malar.
h, h.Post-frontal.
i, i.Parietal.
k, k.Temporal.
l, l.Tympanic.
m, m.Mastoid.
n, n.Nasal apertures.
o, o.Orbits.
oc, oc.Basi-occipital.
t, t.Temporal fossæ.
t′, t′.Canine teeth in the upper jaw.
Lower Jaw.
1.Dentary bone.
2.Coronoid.
3.Opercular.
4.Angular.
5.Articular.
6.Surangular.

The most striking character in these crania is the presence of a pair of long, sharp-pointed, gently curved tusks, implanted in the superior maxillary bones, and which descend, one on each side of the fore-part of the lower jaw, as seen in Ligns. [232] and [233], t, t′. This is a dental character which, with this exception, is peculiar to the mammalia (the Walrus, Musk-deer, and Machairodus), and is rare even in that class.

Examination of the skull.—One of the crania showed the median undivided process of a single intermaxillary bone, ascending and separating two distinct anterior nasal apertures; in another, the boundaries of a very much contracted cranial cavity were evident: these characters combined to prove that the skulls were referable to air-breathing oviparous and cold-blooded animals, or Reptiles; but neither to Crocodilians nor Chelonians, and for the following reasons:—