1890.] HELODERMA SUSPECTUM. 229 



The Pelvic Limb. — As in the case of the anterior limb, we find the 

 long bones ot" this pelvic extremity culminatina; 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 eUipsoid, rearing somewhat above the process seen at 

 the preaxial side of it, which represents the trochanter. A pit is 

 seen for the Ugamentum teres, and this is partly excavated at the 

 expense of tlie 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 Ugamentum patellce, 

 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 oblite- 

 rate the original sutural landmarks. For even in fully adult specimens 

 an examination of this now single bone reveals tbe limitations of 

 three segments that compose it ; these we take to be a tibiale (astra- 

 galus), a fihulare (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 tihio-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, we are to 

 note that in the rase of tnrsale 1 and 2 they appear only to be 



[83] 



