II. On the epipubis in the dog and fox

Abstract

In 1871 I gave a brief description of a structure which I had observed in the dog, in the following terms:— “In the myology of the dog, the insertion of the tendon of the external oblique muscle of the abdomen presents some interesting peculiarities. The outer and posterior fibres of this muscle end in a fascia, which is partly continued over the thigh as fascia lata , and partly forms an arch (Poupart’s ligament) over the femoral vessels; by its inner end it is inserted into the outer side of a triangular fibro-cartilage, the broad base of which is attached to the anterior margin of the pubis, between its spine and the symphysis, while its apex lies in the abdominal parietes. The internal tendon of the external oblique unites with the tendon of the internal oblique to form the inner pillar of the abdominal ring, and is inserted into the inner side of the triangular fibro-cartilage. The pectineus is attached to the ventral face of the cartilage; the outer part of the tendon of the rectus into its dorsal face; but the chief part of that tendon is inserted into the pubis behind it. This fibro-cartilage appears to represent the marsupial bone, or cartilage, of the Monotremes and Marsupials.” The only reference to this statement which I have met with is by Professor Macalister, in his “Introduction to the Systematic Zoology and the Morphology of Vertebrate Animals” (1878), p. 265:— “Professor Huxley describes a fibro-cartilaginous 'marsupial’ above the pubis, from whose anterior surface the pectineus arises. I have failed to satisfy myself of its existence as a constant structure in many dogs, in the common and Bengal foxes, in the dingo, jackal, Canis pallipes , and wolf.”