| OCR Text |
Show 1882.] ANATOMY OF ERETHIZON DORSATUS. 283 The extensor carpi radialis brevior is a larger muscle, and has a stronger tendon, than that last noticed, which overlaps it at its origin. It goes to the third metacarpal. The extensor communis digitorum goes as usual from the external condyle to the four outer digits. The extensor carpi ulnaris takes origin from the external condyle and adjacent parts of the ulna, and goes to the base of the fifth metacarpal. The extensor ossis metacarpi poliicis is large and strong ; it takes origin from the adjacent sides of the radius and ulna, but mainly from the ulna and the strong interosseous ligament. Its insertion is as usual. The extensor minimi digiti, arising from the external condyle, sends tendons to the fourth and fifth digits. The extensor indicis is very delicate; it takes origin from the middle of the exterior surface of the ulna, and sends its tendon to the index. Muscles of the Hind Limb. The gluteus maximus and gluteus minimus I found to be quite similar to those of the Agouti1. The gluteus medius is also as in the Agouti, save that the part of it which is inserted into the hinder side of the great trochanter is more distinct. I did not observe any distinct scansorius. The biceps consists of two parts, which are very similar to those of the Agouti: the first part arises from the sides of the first four caudal vertebrae, and is inserted by a strong tendon into the outer side of the patella; the second part arises (being mainly tendinous at its origin) from the tuberosity of the ischium, external and superficial to the origin of the semimembranosus. It is inserted by fascia into the patella, the tuberosity of the ischium, the head of the fibula, and the external malleolus, and into the fascia which invests the outside of the leg. The most slender accessory muscle of the biceps, or tenuissimus, takes origin from the strong fascia which binds down the dorsal caudal muscles at the root of the tail, on a line with the great trochanter, and at the anterior end of, and covered in by, the origin of the first part of the biceps. It is inserted into the heel and inner side of the sole of the foot; in its course it lies close to the hinder border of the second part of the biceps; at its insertion it unites with the plantar fascia, having a certain adhesion to the inner side of the tuberosity of the os calcis, and more to the plantar surface of the extra tarsal ossicle. The semimembranosus also consists of two parts: one part, thick and fleshy, arises from the tuberosity of the ischium and the ramus below it. It goes to the upper half of the tibia (covered in by the 1 See P. Z. S. 1866, p. 405. What was therein taken to be the tensor vagina femoris I now believe to be the sartorius. |
