On the myology of the sciuromorphine and hystricomorphine rodents / by F.G. Parsons.

  • Parsons, Frederick Gymer, 1863-1943.
Date:
1894
Catalogue details

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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    occiput, from the ligamentum nuchae, and from the anterior three or four dorsal spines and supraspinous ligaments ; the insertion is into the whole length of the vertebral border of the scapula, the occipital fibres also going to the fascia over the inner part of the supraspinatus. Sciurus and Pteromys differ in having a slight separation between the occipital and cervical portions, but this is not seen in Xerus and Spermophilus. Serratus Magnus and Levator Anguli Scapulas.—These two muscles are in the same piano and usually have a continuous origin, so that it is difficult to define their line of demarcation. They rise from the transverse processes of several cervical vertebra, and from the sides of 7 to 9 of the anterior ribs by fleshy digita- tions. The insertion is into the vertebral border of the scapula. In the following animals a separate slip rising from the atlas was found :—Myopotamus, Spliingurus, Lagostomus, Sciurus, Pteromys, and Arctomys. The exact number of vertebra and ribs from which these muscles arise in various Eodents are as follows :— Dipus cec/yptius 1-7 c. v. 1-8 ribs. Capromys pilorides . 2-7 77 1-9 77 „ melanurus1 .... 3-7 77 1-6 77 Aulacodus ... 2-7 77 1-9 77 Myopotamus 1st & 3-7 77 1-8 77 Octodon 5-7 77 1-8 77 Jiystrix 4-7 77 1-8 77 Sphingurus 1-7 77 1-7 77 Chinchilla 2-7 77 1-9 77 Lagostomus 1-7 77 1-8 77 Dasyprocta cristata . 2-7 77 1-8 77 Cceloqenys 1-7 77 1-8 77 Cavia cobaya 1-7 77 1-9 77 Cere cl on 2-7 77 1-9 77 Sciurus 1st & 3-7 77 1-8 77 Pteromys 1-7 77 1-7 77 Xerus 4-7 77 1-8 77 Arctomys mcirmotta .. 1st & 3-7 77 1-9 77 Castor canadensis .. . 2-7 77 1-7 77 Serratus Posticus.—This muscle varies very much in different genera and apparently in different individuals. Aulacodus seems to show most satisfactorily its full development. In this animal the anterior part of the muscle rises from the ligamentum nuchae and spines of the anterior dorsal vertebra to be inserted into the ribs from about the 4th to the 12th, the direction of its fibres being backwards and outwards. The posterior part rises from the spines of the posterior dorsal and lumbar vertebra by means of the lumbar fascia, and runs forwards and outwards to the posterior 1 Dobson, P. Z. S. 1884, p. 234. Proc. Zool. Soc.—1894, No. XIX. 19 [27]