The adjacent side of the table-case shows the modifications of the backbone, or vertebral column, of the ribs, and of the limbs, in the different groups of the class. Specially noticeable are examples of five types of Skink-like Lizards, exhibiting the gradual diminution in the size of the limbs and their final disappearance.
The opposite, or north, side of the table-case displays the different modifications of the skull and teeth of living and extinct Reptiles. In some, like Crocodiles and Ichthyosaurs, the jaws are armed with a full series of sharply pointed teeth, while in others, like the Tortoises and Turtles, they are devoid of teeth and encased in horn. Very remarkable is the approximation to a carnivorous mammalian type presented by the dentition of some of the extinct mammal-like Reptiles, or Theromorphs, and equally noticeable are the palatal crushing teeth of certain other extinct Reptiles known as _Placodus_ and _Cyamodus_. The peculiar dentition of the New Zealand Tuatera, and likewise that of its extinct European and Indian ally _Hyperodapedon_ (fig. 9), are also shown.
FIG. 9.--SKULL OF THE GIANT TUATERA (_Hyperodapedon gordoni_), from the Triassic Sandstone of Lossiemouth, Elgin, (¼ nat. size). A, upper surface of skull; B, palatal aspect of skull; C, under side of front of lower jaw; _Pmx_, premaxillary bone; _Mx_, maxillary; _Pl_, palatal teeth; _Md_, lower jaw; _O_, orbit, or eye-socket; _N_, nostrils; _S_, temporal pit; _S’_, lateral temporal fossa. ]
The brain and other internal organs of Reptiles are displayed in the left half of the wall-case on the north side of this bay, in which are also shown the eggs of many species, in some cases with the embryo.
FIG. 10.--SKELETON OF THE GREAT BLUE SHARK (_Carcharodon rondeletii_), with portion of backbone on a large scale. _pl_, functional upper jaw, and _su_, its reflected portion; _md_, lower jaw; _hy_, ceratohyal; _br_, branchial arches; _co_, pectoral girdle; _ph_, cartilaginous portion of pectoral, or front paired fin; _r_, dermal portion of pectoral fin; _pu_, pelvic, or hind paired, fin; _c_, centra, or bodies, of the vertebræ; _na_, neural, or upper, and _ha_, hæmal, or lower, arch. The median fins are not lettered. ]
