THE SCALES IN SOME TELEOSTEAN FISH. 39 
The Development, Structure, and Morphology of 
the Scales in some Teleostean Fish. 
By 
H. W. Marett Tims 
(King’s College, Cambridge). 
With Plate 6, 
INTRODUCTION. 
Tae interest attaching to a precise knowledge of the 
structure and development of the scales of fishes is twofold. 
Not only may it throw light upon the affinities between 
groups of existing fishes and their evolution, but it helps 
to elucidate the problems involved in regard to tooth-gene- 
sis; for there can be but little doubt that scales and teeth 
are homologous structures. 
It was from the latter point of view more particularly that 
Iwas led to an investigation of the subject, which I com- 
menced during the summer of 1902, in the Gatty Marine 
Laboratory at St. Andrews, where, through the kindness of 
Professor McIntosh, F'.R.S., 1 was permitted to work. 
In the first instance I confined myself to an examination of 
the structure and development of the scales in the Gadide, 
especially in G. virens and G. callarias, of which I 
obtained fairly complete series from Professor McIntosh’s 
rich stores. I further examined specimens of G. minutus, 
G. eglefinus, G. merlangus, and G. pollachius. 
Some of the results obtained were laid before the Zoological 
Section of the British Association at its meeting at Belfast 
in the form of a preliminary communication. 
Since that time I have further examined material supplied 
