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Show 1890.] HELODERMA SUSPECTUM. 229 The Pelvic Limb.-As in the case of the anterior limb, we find the long hones of this pelvic extremity culminating at their proximal and distal ends in epiphyses composed of calcified cartilage, and the sutural traces between them and the true bone of the shafts are visible throughout the life of the individual. One of these superadded pieces caps the trochanter of the femur, a bone which here has a length of about 3'5 centimetres. Its shaft is cylindrical in form and nearly straight; the head which surmounts it (mostly epiphysial) is a transverse ellipsoid, rearing somewhat above the process seen at the preaxial side of it, which represents the trochanter. A pit is seen for the ligamentum teres, and this is partly excavated at the expense of the epiphysis, and partly at the expense of the shaft adjacent. Distally, the condyles are rounded in front, with a shallow rotular channel between them ; while upon the posterior aspect they are especially sculpt in order to articulate with the corresponding surfaces presented on the part of the proximal ends of the two bones of the leg. A very small osseous patella is visible in the ligamentum patellae, at a point opposite the knee-joint. Transverse sections made at the proximal, middle, and distal parts of the shaft of the tibia are seen to be triangular, subcircular, and subtriangular, respectively. The head of this bone is much enlarged, less so its distal extremity, while its shaft is but slightly curved along its lower third. The cnemial ridge is pretty well marked as are the tuberosities at its summit, intended for articulation with the femur. Quite straight and slender, the fibula has a very small proximal extremity as compared with that of the tibia, while its distal end is transversely widened out, being markedly compressed in the antero-posterior direction. These two bones of the leg are of about equal length, each averaging 2-5 centimetres, or about one centimetre longer than the femur. Returning for a moment to the knee-joint, we are to note the presence of the internal and external semi-lunar fibro-cartilages, but the osseous sesamoids found in these parts in some Lizards (Lacerta) are here only performed in cartilage. In this last statement, of course, I do not include the patella. Co-ossification is extended to all the elements of the proximal row of the tarsus, but this fusion is not so complete as to entirely obliterate the original sutural landmarks. For even in fully adult specimens an examination of this now single bone reveals the limitations of three segments that compose it; these we take to be a tibiale (astragalus), a fibulare (calcaneum), and the centrale. The last-named one is very large, comparatively, and may include an intermedium, but there is no evidence of it. Proximally, this tibio-fibulare has a large facet upon either side to accommodate in articulation the fibula and the tibia, while distally it is in contact with the tarsalia and two of the metatarsals. Passing to the consideration of the tarsalia themselves, w e are to note that in the case of tarsale 1 and 2 they appear only to be |