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Show 474 DR. J. MURIE ON SAIGA TARTARICA. [June 9, The remnant of, or aborted fibula, as in other Ruminants, is represented by a short stalactic process of bone depending from the external tibial tuberosity, and by a small subquadrate-shaped boire impacted along with the tarsal elements at the tibial distal extremity ; the latter, as above said, takes the place of an outer malleolus. The tarsus is composed of five separate bones, and a sixth if the fibular distal appendage or separate tarsal-like end be included. These altogether are not so stout as in the Sheep or Chamois. The calcaneum is strong, of moderate length and thickness, and somewhat more than usually narrowed in cross thickness. It mainly articulates with the astragalus ; but there is a facet which rests upon the upper surface of the cuboid portion of the combined naviculo-cuboid bone, and another for the infrafibular ossicle. The astragalus has the ordinary Ruminant type, but relatively is of small size, though its ligamentous pits and impressions are deepish. Its distal articulation is chiefly with the navicular portion of the scapho-cuboid. This combined scapho- or navicular cuboid bone is deep compared with its size. Its upper surface, or face of articulation with the astragalus, is biconcave and considerably scooped oflt. The single metatarsal shows little or no sign of segmentation. Like the metacarpal, it is of considerable length, but much the more laterally compressed, or its antero-posterior diameter is the greater. This fore-and-aft depth decreases from above downwards, and at the base or distal end becomes altered, so that it is broader across than from front to back. The upper two-thirds of the posterior surface is fluted ; and at the top of the groove there rests a small sesamoid bone. The trochlear or digital articular eminences are deep, but not wide. Two pairs of sesamoid bones, affording pulley-superficies for the flexor tendons, lie behind the distal enlargement. As regards length, lateral compression, shape and number, the digits and phalanges of the hind foot agree closely with those of the fore foot. (C) The limb-structure compared.-In reviewing the appendicular structures I may, first, refer to the Table which I have drawn up to exhibit the comparative lengths of the limb-segments in a series of Ruminants. (See p. 475.) Saiga is there placed alongside the Sheep. The numbers attached to the names refer to the individual skeletons in the College of Surgeons' Museum, from which these measurements were taken. A single species of each group may serve for comparison, though of course this implies approximate rather than exact inferences. With regard to greatest breadth of scapula to its length, allowing the long diameter to be represented by 100, these are as under-noted :- 38*1 Giraffe. 59*8 Bull. 68*0 Sheep. 56-4 Goat. 60*0 Saiga. 68*1 Musk-Deer. 59*0 Gazelle. 67*1 Fallow Deer. 69*6 Llama. These proportions, added to the general appearance heretofore men- |