482 



DR. G. LINDSAY JOHNSON ON THE 



[June 5, 



chief A'arieties met with in this country, were examined by me 

 Mith the same degree of luminosity and classed accordiug to the 

 sliape of their pupils, as shown in the following table, in which I 

 u.se the terms relating to shape in the sense hereinafter indicated 

 and illustrated. 



I examined the animals twice over, first by day-light, and then 

 by gas-light, the results on both occasions being the same. 



© 



Fig. 1. 



a 



I understand bj' : — 



Bound- — Practically a perfect circle. (Fig. 1, a). 



Nearly round or Obtuse round — The area common to two equal 

 circles whose centres are separated by not more than a ^g part of 

 their diameter. (6.) 



Round oval or Rectangidar oval — The common area formed when 

 the circles are separated by about g part of their diameter, (c.) 



Pointed oval or Acute oval — The common area formed when the 

 centres of the circles are separated by ^ or more than a quarter of 

 their diameter, {d & e.) 



It will be seen by the above table that no general rule can be 

 established as regards variety, with the exception perhaps of the 

 blue tabbies, in which no oval pupils were observed. 



The colour of the iris seems to have no bearing whatsoever on 

 the shape of the pupils. Sex likewise does not seem to be any 

 guide, as the following summary of the above table shows : — 



