ORDER II 



SQUAMATA 



163 



lignites of Eott, near Bonn ; and the freshwater strata of Steinheim, Haslach, 

 Giinzburg, Sansan, and Colorado. The most gigantic of all lizards are 



(?) Froigtiana, sp. Plios- 

 pliorite of Qiiercy. Inner anil 

 outer aspect of dentary, i/^. 



Fig. 256. 



Plestiodon cadurcensis, 

 Filhol. Phosphorite of 

 Quercy. Inner aspect of 

 dentary, i/j. 



Pcdaeovaramis cayluxi, Filhol. Phos- 

 phorite of Quercy. Maxillary frag- 

 ment, i/i. 



Megalania and Kotiosaurus, from the Pleistocene river deposits of Queensland. 

 The former is estimated to have been about 10 m. in length, and belongs to 

 the Varanidae. 



Sub-Order 4. OPHIDIA. Snakes. ^ 



Body serpentiform, without limbs, covered with corneous scales. Vertebrae 

 procoeloiis, tvith zygosphene-zyg antrum articulation, and the anterior centra with 

 strong simple hypapophyses. Both upper and lower temporal arcades, columella, 

 sacrum, sternum, pectoral arch, ctbdomincd ribs and haemapophyses are wanting. 

 Parietal unpaired,, without foramen, the sides extended downward and fused 

 tvith the probtic, alisphenoid, and orbitosphenoid.. Anterior portion of brain case 

 completely ossified. Quadrate and pterygoid movably attached to skull by ligament. 

 Maxillae and palatines usually freely movable, always displaceable. Premaxillae 

 much reduced ; mandibular symphysis ligamentous. 



Snakes are chiefly conspicuous for the absence of limbs. The body is 

 greatly elongated, and the number of vertebrae very considerable, sometimes 

 exceeding 400. The centra are concave in front and 

 convex behind, the connection being by free ball-and- ^^ ^ ^^ 



socket joints ; and their articulation is further 

 strengthened by zygapophyses and a zygosphene- 

 zygantrum arrangement. The neural arches are 

 thoroughly coossified with their centra. Simple 

 hypapophyses are developed by the anterior ver- 

 tebrae as far as sometimes the thirtieth, and the 

 transverse processes are short and tumid (Fig. 258). 

 Ribs are almost always present in the trunk region, 

 beginning with the third vertebra ; and being freely 

 articulated, are able to assist in propelling the body. Recent; Sumatra. Anterior 



mi 1 1 IP ,1 1 n • ji cervical vertebrae, i/i. (a, Atlas ; 



ihey are long, curved, and irequently hollow; in the cp, Axis; nyp, Hypapnphy.'sis ; 

 caudal region they are replaced by elongate trans- S'X,;.f ' ^'""'"^^ 'P"^*^^' ^^^'"" 

 verse processes. Haemapophyses are wanting among 



snakes, and in their stead occur stout descending bi'anches of the transverse 

 processes (Fig. 259). 



^ Literature : 



Cope, E. I)., Tlie Vertebrata of the Tertiary Formations of the West (Kept. U. S. Geol. Surv. 

 Territ. vol. III.), \%m.— Filhol, H., Ann. Sci. Geol. vol. VIII. (1887), p. 210.— Fischer, G., De 

 serpentibus quibitsdam fossilibus dissertatio. Bonn, 1857. — Meyer, H. von, Coluber atavus aus 

 dem Siebengebirge (Palaeontogr. vol. VII.), 1860. — Rochehrune, A. F. de, Kevision des Ophidiens 

 fossUes (Nouv. Arch. Musee d'Hist. Nat. Paris [2], vol. III.), Id>%0.—Roemer, F., Ueber Python 

 euboeicus (Zeitschr. deutsch. geol. Ges. vol. XXII.), 1870. 



Fig. 25S. 

 Python bivittatus, Sehu. 



