EETTNA OF LATERAL EYES OF SPHENODON PUNCTATUS. 307 
pairs (presumably double cones) in isolation preparations, 
but very seldom joined together to the foot. All these 
sense-cells resemble so closely the generally accepted types 
of cones in other forms, that it seems unnecessary to regard 
Sphenodon as an exception to the general rule in Reptilia 
that cones only are present without rods. 
Further, Osawa states that he could not find any distinct 
“area* centralis ” (i. e. macula lutea). I find, on the 
other hand, that the macula lutea is well developed and 
possesses a perfectly distinct fovea centralis as shown in figs. 
1 and 2. Kallius (20) has since, in answer to Osawa, 
described and figured a well-formed u area centralis” in 
Sphenodon. He mentions that rods are present in the 
central fovea very closely packed together, but the oil- 
globules show these to be really cones. His photograph of 
the area centralis quite closely resembles the appearances I 
have seen. Osawa (24), in reply, states that he has seen the 
“ area centralis ” mentioned by Kallius, but in his subsequent 
account he still appears to think it coincident with tlie blind 
spot. That this is not the case will be seen in my fig. 1 . 
Kallius’ material does not appear to have been in a very 
good state of preservation, and he gives no histological 
details as to the structure of the retina. 
II. Methods. 
When this work was begun all the available paired eyes of 
the specimens used by Professor Dendy for his memoir ( 8 ) on 
“ The Pineal Organs and Adjacent Parts of the Brain in the 
Tuatara (Sphenodon punctatus)” had, as I have above 
stated, been already fixed and preserved. The material may 
be classified as follows. 
(a) Flemming Material. — The eyes of Sphenodon V 1 
1 The numbers are those given by Professor Dendy in the memoir 
referred to, p. 231, but the lateral eyes were in all cases removed and 
preserved quite separately and sometimes by different methods from 
those employed by Professor Dendy in liis own investigations. 
