PINEAL BYE IN LACERTILIA. 215 



the eye is in a more or less highly developed state, its elements 

 often obscured by deposition of pigment, but revealing in all 

 cases, even when best developed, its rudimentary nature by the 

 absence of any nervous connection with the brain. 



(4) Position of the Eye. — With regard to the position 

 of the eye considerable variation is seen. In such forms as 

 Calotes, Leiodera, Anolis, or Agama, for example, the 

 eye is close beneath the external surface, lying in the upper 

 part of the well-marked parietal foramen. In Varanus the 

 eye lies somewhat deeper, whilst in Hatteria it is placed 

 deeper still on the inner side of the foramen, and in both forms 

 a great development of connective tissue takes place, the latter 

 being in every instance arranged in a definite manner. In 

 Lacerta ocellata and Cyclodus the eye is placed within the 

 parietal foramen, fitting it closely, the foramen having the 

 form (see PL XVIII, fig. 27) of a truncated cone, whose apex 

 lies externally. In Ceratophora as per a finally, the parietal 

 foramen is closed, and the modified distal portion of the epi- 

 physis lies quite within the skull cavity. The connective-tissue 

 encasements of the eye also show some variations. In Hat- 

 teria is seen the highest development in this respect, the eye 

 lying in a definite capsule, and having special supporting fibres 

 stretching across to it from the walls in the anterior part. In 

 Varanus the arrangement of the connective-tissue fibres 

 appear to indicate the fact that a capsule formerly enclosing 

 the eye, as in Hatteria, has become filled up with fibres, so 

 that the eye is now immovably fixed. In other forms, again, 

 such as Cyclodus, Anolis, or Anguis, it lies surrounded 

 by vacuolate tissue, whilst in others, as Chameleo, Lacerta 

 ocellata, Leiodera, Monitor, Uraniscodon, Calotes, 

 and various other genera, the connective tissue, without any 

 trace of capsule, closely invests the eye, no space being left 

 within the parietal foramen. 



If now we take typical examples from amongst the Lacertilia, 

 and consider the state of development in each with regard to 

 the above four points, it is seen that no one form shows a high 



