Observations in myology : including the myology of Cryptobranch, Lepidosiren, dog-fish, Ceratodus and Pseudopus pallasii, with the nerves of Cryptobranch and Lepidosiren and the disposition of muscles in vertebrate animals / by G.M. Humphry.

Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: Observations in myology : including the myology of Cryptobranch, Lepidosiren, dog-fish, Ceratodus and Pseudopus pallasii, with the nerves of Cryptobranch and Lepidosiren and the disposition of muscles in vertebrate animals / by G.M. Humphry. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    separated from one another, that is, the lateral muscle of the one side is separated from that on the other by membranous septa passing vertically in the mesial line above and below from the vertebrae; and ossifications extending into these septa above and below constitute the ' neural’ and ‘haemal’ spines. Each lateral muscle is, as in the Fish, divided into an upper or ‘ dorsal’ and a lower or ‘ ventral’ muscle by a horizontal membranous septum—which may be called the ‘lateral septum’ —stretched from the sides of the vertebrae nearly midway be- tween the upper and lower edges of the animal, and ossifica- tions extending into these septa on the two sides would con- stitute ‘transverse’ or ‘lateral’ processes. Such ossification however has not taken place except in the fore part of the tail. Each of the septa (Fig. 1) as it approacees the surface splits into two laminae which extend in opposite directions beneath the skin and meet and unite with the adjacent laminae of other septa. Thus the laminae resulting from the splitting of the neural septum are spread out, right and left, upon the dorsal muscles, and meeting the ascending laminae from the lateral septa, form sheaths enclosing the dorsal muscles. The same is the case with the laminae of the ventral septum; and the four muscles, the two ‘dorsal’ and the two ‘ventral’ of the two sides, are enclosed in sheaths, more or less distinct, formed by the laminae of the neural, ventral and lateral septa. Finally (Fig. 2), the four longitudinal caudal muscles—the two dorsal and the two ventral muscles—are divided trans- versely by septa, extending with more or less obliquity back- wards or forwards from the intervals between the several vertebrae to the enclosing sheaths just described and the skin. So that each of the longitudinal muscles is transversely seg- mented into pieces corresponding with the several vertebrae. These transverse septa are tough and form as it were part of the muscle itself, being connecting media between the ends of the muscular fibres of the segments. They are not disposed in true vertical planes, but form slight curves with the convexity back- wards above and below the lateral septumh ^ Schmidt, Goddard, and van der Hoeven count 46 of these tendinous in- ecriptions, 14’or 15 in the trimk, and the remainder in the tail, where the muscular intervals between them are narrower.