Recent polydactyle horses / by O.C. Marsh.

  • Marsh, Othniel Charles, 1831-1899.
Date:
[1892]
Catalogue details

Licence: Public Domain Mark

Credit: Recent polydactyle horses / by O.C. Marsh. 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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    two united cuneiform bones. Tlie lower extremity of this metatarsal carried a single phalanx, with a posterior sesamoid evidently formed of two hones. The main cannon bone and its phalanges show no marked peculiarities except some obliquity. The fourth digit is represented by a large splint metatarsal, as shown in figure 4. The opposite hind foot appears to be similar in all respects, except that the three small cuneiform bones are separate, as shown in figure 9. Figure 8.—Right carpals and metacarpals of Clique. Figure 9.—Right tarsals and nietatiirsals of same animal. One fourth natural size, a, astragalus; c, calcancum; cb. cuboid: 1, 2, 3, 4, cuneiform bones; /. lunar; m, magnum ; n, navicular; ]), pisiform; s, scaphoid ; td, trapezoid ; tm. trapezium. In no case examined by the writer has there been conclusive evidence of any extra digit except one of a true pentadactyle foot, such as is now known in the ancestry of the horse. In every specimen examined, where the carpal or tarsal series of bones were preserved, and open to inspection, the extra digits were supi^orted in the usual manner. No instances of true digital division were observed, although such cases might be expected. It is noteworthy that none of the extra toes examined repre- sents the fifth digit, although the reappearance of this rather than the first might naturally be looked for. ]^o digit has been noticed with more than three phalanges. A large majority of the polydactyle horses known to the writer in this country, have been raised in the Southwest, or from ancestry bred there, so that their connection with the Mustangs or semi-wild stock of that region becomes more than probable. It is well known that the tendency to reversion is much stronger where animals run wild, and this fact must be taken into consideration in discussing the present question, for the late ancestors of the Mustang were certainly w^ild for at least several hundred years.