168 ME. H. G. SEELET ON OSSEOUS EESEMBLANCES 



proximal articulation is more nearly hemispherical, and has the 

 inner side of the head more developed. In front is a transverse 

 and vertical triradiate notch for the ligamentum teres ; behind, 

 the proximal end of the shaft is compressed. The bone termi- 

 nates distally in a well-rounded trochlear articulation, above 

 which, on the posterior aspect, is a deep depression. 



The tibia and fibula are shorter than the femur — the tibia straight, 

 but the fibula curved like an uhia upside down. The tibia is massive 

 at the proximal end, with a transverse concave articulation adapted 

 to the femur ; its distal end is subcylindrical and obliquely trun- 

 cated. The fibula is compressed behind ; and a shai'p ridge runs 

 posteriorly down its length. 



The tarsals are entirely difiierent. 



The metatarsals are short, like the metacarpals, the elongation 

 of the foot being made by the phalanges ; there is nothing ana- 

 logous to the arrangement of the digits in the Crocodilian hind 

 foot to be seen in the Chameleon. 



§ 4. Tlie Lacertian CJiaracters of Crocodiles. 



Iguana is like the AUigator in having the nostril double, but 

 unlike that animal m having its outer margin made by the maxil- 

 lary bone, and its inner division by a single premaxillary. The 

 frontal and parietal are similarly single ; and the bones generally 

 correspond in their connexions ; only a smaU quadrato-jugal ap- 

 pears to be placed in front of the squamosal at the proximal end 

 of the quadrate bone, so that the malar arch is not prolonged, as 

 in the Crocodile, to the distal end of the os quadratum. And the 

 temporal fossae, which are small in Crocodiles, are here so enor- 

 mously enlarged that they prolong outward and backward, in a 

 V-shape, diverging processes of the parietal bone. The high po- 

 sition of the quadrato-jugal would seem attributable to the great 

 development of the postfrontal in making the outer margin of 

 the temporal fossa. 



There is nothing in common in the arrangement of the bones 

 on the palate, owing seemingly to the elevated shape of the Lizard's 

 head, by which the maxillaries are withdrawn from the palate 

 and the palatine bones go forward to take their places. 



The lower jaw in the Lizard is not perforated behind like that 

 of the Crocodile ; it has the articular bone developed inward to 

 even a greater extent than in Crocodiles, and has the corouoid 



