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Show 230 DR. R. W. SHUFELDT O N [Apr. 1, represented by an inconspicuous intercalated bit of thin cartilage, barely preventing the contact of the tibio-fibulare with the first two metatarsals. Proximal epiphyses of these latter, however, are moulded to meet the ends of perfect articulation. Subcuboidal in form, tarsale 3 is a well-ossified bonelet articulating with second and third metatarsals, with tarsale 2, and with the tibio-fibulare, or the co-ossified mass representing the elements of the proximal row. The basal ends of the 2nd and 3rd metatarsals are markedly smaller than they are in the 1st and 4th, indeed in the latter it has its proximal extremity very conspicuously expanded. Tarsale 4 is a larger nodule of bone-that articulates with the tarsal elements upon either side of it, with the 4th metatarsal, and with the tibio-fibulare. Finally, more remarkable than any of the rest is tarsale 5 ; it is a wonderfully irregular bone in form, and peculiar in other respects. It articulates by merely a vertical line with the tibio-fibulare. Externally it sends forward a prominent process that, by a trochlear facet at its extremity, articulates with the basal phalanx of the 5th metatarsal. It also articulates with tarsale and metatarsale 4, while in the sole it sends downwards a strong process that serves for muscular and other attachments. This latter is augmented by the form assumed by tarsale 4 at its inner side, and it is this common apophysis that gives attachment to some of the short plantar muscles tbat, in m y chapter on the myology (given above), m a y have been a little differently described, from tbe confusing propinquity of the ossicles in question. So that a knowledge of this fact will make clear in those premises what might otherwise be considered not an exact description. Professor T. J. Parker, in his studies oi Lacerta viridis, considered tarsale 4 to be the "cuboid" (Zootomy, p. 152). Vestiges of a very rudimentary character appear to be preseut in one of m y specimens of Heloderma of a sixth pedal ray, it being in connection with tarsale 5 upon the fibular side of the ankle. The metatarsals differ in form but slightly from the metacarpals, and these differences pertain more especially to the proximal extremities, and these have already been pointed out above. Still more insignificant are the differences to be found between the corresponding joints of the digits of manus and pes, and their numerical arrangement is also similar. W e saw in the hand that, passing from the radial to the ulnar side, the fingers possessed 2, 3, 4, 5, 3 phalangeal joints, respectively ; now in the foot, in passing from the tibial to the fibular side these numbers exactly correspond, or we find 2, 3, 4, 5, 3 phalangeal joints to the toe respectively. A n excellent diagnostic character twixt pes and manus in this Lizard is to be found in the comparative size and form of the fifth metatarsal and the fifth metacarpal; in the case of the former it is notably short and small, while in the latter quite the reverse of these characters exists, for no especial curtailment of its length is to be noticed, and in bulk it rather exceeds any one of the middle thiee joints of the palm. |