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Show tHubereerc tlhees. under-side of the toes, like the sole of the foot, is covered with minute Though in the form of the skull Ab•·oM>na Cuvie,.i• ag•·ees most nearly with that of Octodon; it differs in having the anterior portion narrower and rather larger, compared to the part devoted to the p.-otection of the brain; the zygomatic arcl1 is shorter, the incisive foramina arc longer, the body of the anterior sphenoid is narrower, and the auditory bull:e are larger. The principal differences observable in the form of the lower jaw of Abrocoma, when compared with that of Octo<lon, consists in the coronoid process being smaller, the condyloid narrower fmm front to back; the descending mnms more deeply emarginatcd posteriorly, and the angle longer and more attenuated. MAMMALIA. 85 In those characters in which the sku II of Abrocoma departs fi·om that of Octodo.,, it approaches nearer to CltiucMlla. In the peculiar fmm and large size of the em~. in the extreme softness of the fur, in the greater development of the pads on the under side of the toes, and in the possession of only four toes to the fore feet, there are other points of resemblance between .d.b,.ocoma and Ct,;,,c/,iila. In the ChinchBJa as well as in Octodon and .d.brocoma, we find the toe corresponding to the second (coon tin g from the in ncr side) furnished with a broad hollow nail ; t t!Jere are also stiff bristly l1airs covering this nail as in the Octoclontidce. The extreme softness of the fur of the animals about to be described, sugg ·ested for them the generic name of Abrocoma. The fur consists of l1airs of two lengths, and the longer hairs are so extremely slender tlmt they might almost be compared to the web of the spider. The specilic names applied are those of the distinguished naturalists who first made us acquainted with the two genera, Octodon and Poephagornys. 1. ABROCOlllA BENNETTII. PLATE X VIII. Abrocorna Dennettii, lVaterh., Proceedings of the Zoological Society of London, for Fobrunry 1837, p. 31. A. corpo·re supr d griseo, ad latera pallidiore et pallid/ ce,.vino lavato, subtils a/besc~nticerviuo; guM albesceati-grised; pedibus so,.didl albis .- auribus ampZ.s, ad '""'"IP'""' posticurn 1·ectis, ext us ad bases veltere, sicat in corpore, obsitis: ccmdti co17Jore brevzore, ad basin c1·assiusculd, pilis brevibus incumbentibus vestitd. D ESC!UPTION.-Form stout; ears large, wt·t 11 t 1·1 e pos t eu: o r ma<r ·oo- in straight·' fore * I ktvc not had an opportunity of examining the sk ull of Abrocomre Benncttii. . t Tl1is nail no doubt is used to cleanse tlw fur, and the bri tly hairs may also assist in the opcratwn; the two small toes of the Kangaroo's hind foot arc used for the same purpose. |
