572 REPTILES. 



by the paired pro-otics. Internally, an important bone, the epipterygoid 

 or "columella" (not to be confounded with the columella or stapes of 

 the ear), extends from the pro-otic to the pterygoid. The orbit is bounded 

 posteriorly and inferiorly by the jugals. There is no ossified quadrato- 

 jugal, and thus the lateral temporal fossa is open below in the dried 

 skull (contrast Hatteria). The other fossse of the dried skull are the 

 supra-temporal on the upper surface, and the posterior-temporal on the 

 posterior surface. 



Each half of the lower jaw is composed of six bones, which 

 fuse in the adult. The two rami are sutured to one another in front. 



Limbs and girdles. — In the shoulder-girdle, the flat 

 coracoids, with an anterior precoracoidal region, articulate 

 with the sternum, which is represented by a cartilaginous 

 plate of rhomboidal shape. Over it projects the long limb 

 of the T-shaped interclavicle, which, at the sides, is con- 

 tinued backwards by the curved clavicles. The remaining 

 elements are the scapulas, which are continuous with the 

 cartilaginous supra-scapulae. 



The fore-limbs have the usual parts. In the carpus all 

 the typical nine bones are represented, and there is in 

 addition an accessory " pisiform " bone. 



In the pelvic girdle, ilium, pubis, and ischium are repre- 

 sented as usual ; there are both pubic and ischiac symphyses. 



In the tarsus the fibulare and tibiale are united, and the 

 distal row consists of only two bones. 



Nervous system. — The brain consists of the usual parts. 

 The cerebellum is small and only partially overlaps the 

 fourth ventricle. In the region of the thalamus the epiphysis 

 is distinct and conspicuous, but in the adult the pineal body 

 is quite separated from it, and lies in its connective tissue 

 capsule below the skin. 



Alimentary system. — Small pointed teeth are present on 

 the maxillae, premaxillse, palatines, and on the lower jaw. 

 They are fixed without sockets on the edge of the jaw- 

 bones (pleurodont) ; in many Lacertilians they are implanted 

 along the ridge (acrodont). Salivary glands occur on the 

 floor of the mouth cavity. The narrow gullet passes 

 gradually into the muscular stomach, which again passes 

 into the coiled small intestine. Near the commencement 

 of the large intestine there is a small caecum. A voluminous 

 liver, with a gall-bladder embedded in it, and a pancreas, 

 are present as usual. 



