336 



ZOOLOGY 



SECT. 



immediately under the integument, and covered over by a specially 

 modified, transparent scale. Like the epiphysis itself, the pineal 

 eye is developed as a hollow outgrowth of the roof of the dien- 

 cephalon; the distal end of this becomes constricted off as a 

 hollow sphere while the remainder becomes converted into a 

 nerve. The wall of the hollow sphere becomes divergently 

 modified on opposite sides ; the distal side becomes modified to 



P ,,..,^.IJ '.. "/;:; ., 



st 



Vic.. 948. Section of the pineal eye of Hatteria punctata. y, blood-vessels ; h, cavity of the- 

 eye filled with fluid ; k, capsule of connective tissue ; /. lens ; m. molecular layer of the 

 retina ; r. retina ; st. stalk of the pineal eye ; x, cells in the stalk. (From "Wiedersheim, after- 

 Baldwin Spencer.) 



form a lens-like thickening (/), the proximal forms a membrane 

 several layers in thickness the retina (r.) the whole is enclosed 

 in a capsule of connective tissue (k.). The nerve degenerates 

 before the animal reaches maturity, so that the organ would 

 appear though evidently, from its structure, an organ of sight- 

 to have now entirely or nearly lost its function. 



*** 



Reproductive Organs.- -The description already given of the 

 reproductive organs of the Lizard (p. 310) applies, so far as all 

 the leading features are concerned, to all the Lacertilia and to 

 the Ophidia ; in Hatteria the copulatory sacs are absent. In the 



