On the myology of the sciuromorphine and hystricomorphine rodents / by F.G. Parsons.
- Frederick Gymer Parsons
- Date:
- 1894
Licence: Public Domain Mark
Credit: On the myology of the sciuromorphine and hystricomorphine rodents / by F.G. Parsons. 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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![the internal condyle. (3) A slip rising behind this by a very thin tendon from the same origin and running to the middle third of the posterior border of the femur. These three probably represent the adductors longus and brevis. (4) A slip from the tuber ischii running obliquely across the leg to above the internal condyle and also to the posterior surface of the femur above it. This is supplied by the great sciatic nerve instead of the obturator, and is the second part of the semimembranosus joined to the adductors. (5) A massive muscular slip from the outer side of the tuber ischii to the upper part of the shaft of the femur. In Spermophilus, Xerus, Arctomys, and Castor the arrangement is essentially the same, but in Pteromys an extra deep slip was observed running behind the obturator nerve to the upper part of the femur, while the portion described as No. 4 in Sciurus had a much more extensive attach- ment up the femur. Meckel describes five heads in Arctomys. In Castor, although the arrangement is identical with that of Sciums, the muscle is very massive and the separate parts much less easy to identify. Tibialis Anticus.—This muscle usually rises from the upper part of the outer surface of the tibia, and is inserted into the internal cuneiform and first metatarsal by two slips. In those cases in which the halux is absent or rudimentary the tendon does not divide into two at its insertion. In Dipus cegyptius its insertion is into the inner side of the base of the great metatarsal bone. Among the Octodontkke, Myopotamus and Capromys have a double insertion, Aulacoclus and Octodon a single one. In the Ilysl ricidae it has a double insertion (Ilystrix, Spliingurus, Erethizon). Meckel1 says that in Hystrix it is blended with the extensor pro- prius hallucis; but this I did not find. In the Chinchillidte it not only rises from the tibia but from the tendon of origin of the ex- tensor longus digitorum (Chinchilla, Lagostomus). In the Dasyproctidse it rises from the front of the external condyle of the femur by a tendon which is anterior to that of the extensor longus digitorum, as well as by fleshy fibres from the upper part of the tibia; it is inserted by a single tendon, which in Dasy- procta goes to the base of the internal (2nd) metacarpal, and in Coelogenys to the internal cuneiform. In the Caviidse it has the same origin as in the Chinchillidse, and is inserted into the rudimentary fused internal cuneiform and first metatarsal, which is found under the base of the internal (2nd) metatarsal. Mivart and Murie2 found a femoral origin, as in the Dasyproctidse, in some of the Guinea-pigs they dissected. Beddard 3 describes the same arrangement in Dolichotis patagonica. In three Guinea-pigs I have not fouud a femoral origin once, and the specimen of Cercclon rupestris I dissected did not show it. I also did not see it in D. patagonica. Further observation is needed 1 Op. cit. p. 410. 2 P. Z. S. I860, p. 383. 3 P. Z. S. 1891, p. 236. [38]](https://iiif.wellcomecollection.org/image/b2238635x_0042.jp2/full/800%2C/0/default.jpg)
