On a new genus of the order Rodentia / by Joshua Brookes.

  • Joshua Brookes
Date:
1829
Catalogue details

Licence: Public Domain Mark

Credit: On a new genus of the order Rodentia / by Joshua Brookes. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    author, indeed, appears to have doubted the propriety of this location, and mentions with evident regret, that the loss of the remains of the animal had prevented our becoming acquainted with its organization, and ascertaining precisely its characters. Fortunately, however, the animal, although obscured from notice during so long a period, is yet in a condition for accurate and minute examination. The description of its preserved skin and skeleton I have now the honour of presenting to the notice of the Society ; and from the structure of the latter especially, it will be evident that it must be referred to a new genus, to which I propose to give the name of Lagostomus. The form of the teeth, on which so much stress is justly laid in characterizing genera, differs essentially from that exhibited by all the other Rodentia; from which it is also distinguished not only by the number of its toes, but by various other particulars of its osteology, which I shall now proceed rapidly to describe, assuming occasionally as a point of comparison the skeleton of the Dipus Sagittc, with which it has been generically confounded. The upper surface of the cranium in Lagostomus exhibits the usual form of that of the Rodentia, its sides being nearly pa- rallel, and its occipital breadth scarcely exceeding its breadth immediately anterior to the orbits. In Dipus, on the con- trary, the outline is decidedly triangular, arising from the very considerable dilatation of its hinder part, occasioned by the extraordinary development of the mastoid processes of the tem- poral bones, which are extremely delicate, and possess, as in man, a cellular structure*. The * The Egyptian Jerboas being known to domiciliate themselves under bushes fre- quented by the Cerastes, so that it frequently, or perhaps generally occurs, that where the one, there the other is also found ; this particular osseous extension may be destined by Nature, to give increased sensitiveness to the auditory organ, for the greater secuiity of the animal. In the Chlamyphorus truncatus there are two somewhat similar osseous tumours
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