88 REPTILES AND BATRACHIAKS. 



of the skull ; " and a pineal eye " from its connection with the 

 pineal gland situated in the brain ; and the strange part about it is 

 that while a pair of perfect eyes have been subsequently developed 

 and are in use, this buried organ seems never to have advanced 

 beyond those found in the invertebrate groups, presenting, as 

 Von Henri de Graaf at first described it, " the important example 

 of the two kinds of eyes being present in the same animal." In 

 Anguis fragilis the organ is too deeply embedded to be affected 

 even by light ; but in the New Zealand lizard, Hatter ia, or 

 Sphenodon punctatus, de Graaf found a well-marked nerve con- 

 nected with the brain. The very interesting subject has been enthu- 

 siastically taken up by many biologists, and the results of their 

 labours introduce wonders almost daily. In England Professor 

 Baldwin Spencer, late of the Oxford University Museum, who has 

 been examining all the lizards alive or dead that can be got at, 

 and also fossil remains, shows us that in some lizards the eye is so 

 near the surface that its functional power is even possible ; and 

 from America we hear of one, the " common pine-tree lizard," 

 in which the organ is so well developed that " it may possibly 

 still serve to warn its owner of the advent of daylight." 



In Anguis fragilis Prof. J. Beard (see p. 43) finds the parietal 

 eye to vary in size and distinctness, though so deeply embedded 

 as to preclude the idea of its being affected with light. In some 

 lizards at the Zoological Gardens you may detect the spot where 

 this eye exists, though without a powerful magnifier nothing 

 more than the external scale, often transparent, can be seen. In 

 our two little British lizards, forming the subject of the following 

 chapter, we will presume on the existence of this median eye. 

 What has been said of other kinds suffices for the scope of this 

 work. 



