182 W. BALDWIN SPENCER. 



external indication of the structure Varanus thus differs 

 much from Hatteria in the possession of this scale, modified 

 to form a cornea. 



Position of the Eye. — The cornea thus formed lies imme- 

 mediately above the parietal foramen, the space in which is 

 tightly filled by connective tissue, in the midst of which again 

 lies the pineal eye. There is thus no real cavity beneath the 

 cornea, but the pigment, which elsewhere is abundantly present 

 in the skin, is here entirely absent, so that by this means the 

 passage of light to the organ is much facilitated. Beneath the 

 epidermis and the rete mucosum the connective-tissue fibres 

 of the cutis vera are arranged in two definite sets, as in 

 Hatteria: (l)a series running parallel to the anterior surface 

 of the eye from side to side of the foramen (PI. XIV, fig. 1, 

 Ct^), interlacing with each other, and thus forming a dome- 

 shaped structure above the eye ; and (2) a series of bundles 

 {Ct^) at right angles to the former, upon which they spread out 

 at their internal ends, whilst externally they run outwards 

 to the rete mucosum. Obliquely directed strands pass from 

 one bundle to another, and the irregular spaces thus left are 

 filled up by a mesh work of indefinitely arranged fibres. 



Immediately below the level of the first series of fibres is 

 placed the eye itself, but, instead of lying, as in Hatteria, in a 

 capsule, the connective tissue closely invests it. The tissue 

 within the parietal foramen may be divided into three parts : 

 (1) a series [Ct^) bounding the sides of the parietal foramen, 

 and continuous with the upper series {Ct^); these follow in their 

 course the outline of the bone ; (2) irregularly arranged fibres 

 (C/*), filling up the greater part of the foramen; (3) a series 

 forming a special encasement for the eye, to the sides of which 

 their long axes are parallel {Ct^, the arrangement of these is 

 scarcely made sufficiently prominent in the figure). 



In Hatteria is found a special capsule in the space within 

 which the eye is situate. Even in this form a certain amount 

 of connective tissue lies within the capsule, whilst a still greater 

 development of the tissue would lead to the condition which 

 obtains in Varanus gigauteus. 



