nasal aperture *, which, moreover, in Mosasaurus looks directly upwards instead of upwards and forwards, in the total obliteration of the maxillo-praemaxillary suture, which, in Mosasaurus, remains as a well-defined groove, and, lastly, in the absence from its cylindrical teeth of the opposite denticulated ridges, the total range of variation in the teeth of Mosasaurus including at most teeth exhibiting the suppression of one of these (the anterior), and that on the pterygoid teeth†.
I propose for this reptile the name of Acrodontosaurus Gardneri— the first obviously in allusion to the mode of attachment of its teeth, the second out of compliment to my indefatigable friend.
The strata of the locality whence this fossil came were so fully and ably described by my friend Mr. Etheridge in fixing the position of Acanthopolis horridus, Huxley, that it will only be necessary to say that it was obtained by Mr. Griffiths from the Lower Chalk of Lyddon's Spout, near Folkestone, about 10 feet above the Chalk marl.
It will, I think, be better to leave the discussion of the affinities of this reptile till further discoveries furnish a better character for our guidance than the mode of implantation of the teeth,
EXPLANATION OF PLATE XIX.
Fig. 1. Side view of upper jaw of Acrodontosaurus Gardneri, nat. size : b, process of praemaxilla ; c, osseous base of shed tooth ; /, terminal facet ; g, groove.
2. Front view of the same : b & f as in fig. 1.
3. View of fractured hinder end ; a, inner projection.
13. RODENTIA of the SOMERSET CavES. By W. Ayshford Sanford, Esq., F.G.S.
(The publication of this paper is deferred.)
[Abstract.]
The author has examined the Rodents from the caves of Somersetshire contained in the Taunton Museum, and found that many of them cannot be referred to species hitherto regarded as belonging to the fauna contemporary with the Mammoth in Britain. He enumerates species of Arvicola (including A. glareola, Schreb., and A. ratticeps, Blas. =Lemmus medius, Nilsson, and a species which may be new, and for which he proposed the provisional name of A. Gulielmi), Lemmus (L. norvegicus, Desm.), Lagomys (L. speloeus, Owen), Lepus (L. diluvianus, Pict., L. timidus, Linn., L. hibernicus, Bell, and L. cuniculus, Linn.), Spermophilus (S. erythrogonoides, Falc. : the citation of S. citillus by the author and Mr. Boyd Dawkins is founded on a mistake), and Cricetus (C. songarus, Pall.).
- Goldfuss in Nova Acta Acad. Nat. Cur. vol. xxi. p. 1, tab. vi.-viii.
† Teste Dr. Leidy.
