1902-3.] Mr J ohn Cameron on the Pineal Body. 
577 
There were thus examined fourteen specimens representing the 
frog, twelve specimens representing the toad, and eleven specimens, 
representing the newt. 
It will be observed that towards the later stages of development 
the epiphysial opening tends to become more and more mesial in 
position. 
The embryos were all reared in the laboratory and their ages 
calculated from the date of fertilisation. It was, however, found 
impossible to ascertain the date of fertilisation of the newts’ ova ; 
but, since they appear to develop at the same rate as those of the 
frog and toad, when reared in the laboratory, their ages as given 
in the above list are probably correct. 
The sections of the newt-embryos were all prepared in the 
laboratory of Professor His at Leipzig, and those of the frog- and 
toad-embryos in the Anatomy Department of the United College, 
University of St Andrews. To both Professor His and Professor 
Musgrove the author begs to offer his most sincere thanks for all 
the valuable opportunities which have been granted to him for the 
furtherance of this research. It is intended to continue these 
researches in the case of Birds and Mammals in order to ascertain 
whether any evidence of the primary bilateral epiphysial condition 
exists in these higher vertebrate classes. 
III. Summary and Conclusions. 
1. The epiphysis cerebri in certain types of Amphibia arises 
in the form of two recesses from the roof of the fore-brain. 
These are placed one on either side of the mesial plane. 
2. The recess which is situated to the right of the middle line 
never gives rise to a distinct evagination of the roof of the fore- 
brain, but disappears at an early stage of development by blend- 
ing with the left recess. 
3. The latter shows the more active growth, and the effect of 
this in most cases is to cause the epiphysial opening to become 
situated to the left of the middle line (by the twelfth day). 
4. These primary epiphysial recesses in Amphibia correspond 
to the right and left epiphysial outgrowths described by Beraneck 
(4) in Lacertilia, Dendy (9) in Hatteria, and by Hill (16 and 
