202 JR. B. Newton — On the Genus LeveilUa. 



curvature of Mammoth tusks. The transverse measurement in a 

 straight line between the extremities of the horn cores, which are 

 nearly parallel to each other, is 8 feet 6^ inches measured by M. 

 Peringuey. But on the right side the curve extends 1^ inch further 

 outward from the middle line of the skull than on the left side. M. 

 Peringuey, of the South African Museum, had the kindness to verify 

 for me Mr. A. G. Bain's measurement ; and as now preserved the 

 length along the posterior or concave curvature is 11 feet 1 inch, 

 which corresponds sufficiently with 11 feet 7 inches obtained by Mr. 

 Bain probably by taking the outer curve. The horn cores are also 

 remarkably cylindrical, the flattening being moderate, a character of 

 some interest when compared with the flattened form of the horn 

 cores in the large Buhalus palceindicus of the Nerbudda. The face 

 is long and narrow, rounded above the orbits, flattened from side to 

 side and concave in length between the frontal and nasal region. 

 The length of the head as preserved is 22|- inches, but with the 

 slight restoration at the back of the head and the lost premaxillary 

 prolongation in front it would be several inches longer. In general 

 character this fossil approaches nearest to the South African Buffalo, 

 so far as can be judged from its state of preservation ; and it probably 

 bears much the same relation to that type which the Bos primi genius 

 of our own gravels and superficial deposits has to existing British 

 cattle. It is not without interest to find that South Africa is no 

 exception to the general law, that some of the existing races of 

 animals have been preceded by allied species of larger size, as in 

 Europe, South America, and Australia. 



I am indebted to a grant from the Government Grant Fund of 

 the Eoyal Society for the opportunity of identifying the specimen 

 described fifty-two years ago by Mr. Bain. The figure is from a 

 photograph taken for me by Mr. Allis, of Eosebank, Cape Town, 

 and is on the scale of about one millimetre to the inch. 



III. — On the Genus Leveillia (Porcellia, Leveille), with a 

 Notice of a New Species fkom the Carbonifekous Limestone 

 OF Ireland. 



By E. BuLLEN Newton, F.G.S., 

 of the British Museum (Natural History). 



(PLATE VI.) 



IN 1835 M. Charles Leveille^ described a peculiar and extinct 

 univalve shell under the name Porcellia, which he had discovered 

 in the Carboniferous Limestone of Tournay in Belgium. Since that 

 time the right of this name to stand has never been questioned, not- 

 withstanding the fact of its pre-occupation by Latreille ^ in 1804, 

 for an Isopodous Crustacean genus, and which he rendered Forcellio. 

 As the retaining of two names so nearly alike, differing only in their 

 terminal letter, must constantly lead to confusion in Natural History 

 nomenclature, it becomes necessary to suggest an alteration, and 



1 Mem. Soc. Geol. France, 1835, vol. ii. part 1, p. 39. 



2 Hist. Nat. Crust. 1804, vol. vii. p. 45. 



