Part 35

Footnote 27:

They are naked, but I suspect the hair has been rubbed off.

Footnote 28:

I am acquainted with seven North American Species of Muridæ, all of which possess the dentition of Hesperomys.

Footnote 29:

Ἐσπερος, West, and Μυς.

Footnote 30:

I am acquainted with only one exception, and that is in the genus Castor. In the genus Ondatra, the descending ramus is but slightly twisted outwards, but in all the other Arvicolidæ, whose crania I have examined, it is remarkably so, and in the genera Spalax and Geomys, where this character is carried to the extreme, the descending ramus projects from the alveolus of the long inferior incisors, in the form of a rounded and almost horizontal plate.

Footnote 31:

In aged individuals of some of the species of Arvicolidæ, the molar teeth possess short roots. In a skull of Ondatra now before me I find all the molars divided at the base into two portions, which in all probability would have formed solid roots had the animal lived longer.

Footnote 32:

See Proceedings of the Zoological Society for April 9th, 1839, p. 61.

Footnote 33:

Azara’s Voyages dans l’Amerique Meridionale, vol. i. p. 324.

Footnote 34:

Transactions of the Zoological Society, vol. ii. p. 84.

Footnote 35:

Azara Voyage dans l’Amerique Meridionale, vol. i. p. 324.

Footnote 36:

Compendio de la Hist. Nat. del Reyno de Chile, vol. i. p. 343.

Footnote 37:

Ἁβρος, soft; Κομη, hair.

Footnote 38:

There is a wide difference between the present animals and the Arvicolidæ in the form of the occipital condyles: the same difference is also observable between Echimys and Mus. The Octodontidæ in fact have the same form of condyles as the Chinchillas and Cavies. In this and many other characters the last mentioned animals evince an affinity to the Leporidæ.

Footnote 39:

I have not had an opportunity of examining the skull of Abrocoma Bennettii.

Footnote 40:

This nail no doubt is used to cleanse the fur, and the bristly hairs may also assist in the operation; the two small toes of the Kangaroo’s hind foot are used for the same purpose.