OBSERVATIONS ON FISH SCALES. 
By T. D. A. COCKERELL, 
University of Colorado, Boulder, Colo. 
INTRODUCTION, 
In a paper on “The Scales of Freshwater Fishes” (Biological Bulletin of the Marine 
Biological Laboratory at Woods Hole, Mass., vol. xx, May, 1911) I have given an 
account of the recent work on teleostean fish scales and have discussed some of the 
problems presented by the scales of freshwater fishes. Until recently it has been impos¬ 
sible to do much with the scales of marine fishes, owing to the difficulty of obtaining 
adequate materials. For the same reason very little was done on the spiny-rayed 
freshwater groups, the Percidae, Centrarchidae, etc. During the summer of 1911, 
however, I was enabled to continue the work in the laboratory of the Bureau of Fisheries 
at Woods Hole, where the director, Dr. F. B. Sumner, afforded me every possible facility 
and put at my disposal a large series of fishes representing many families. I have also 
been very greatly indebted to the Bureau of Fisheries, through Dr. Hugh M. Smith and 
Dr. B. W. Evermann, for numerous and important specimens from the collections at 
Washington. At the National Museum Mr. B. A. Bean and Mr. A. C. Weed gave me 
much help and supplied scales of some important genera, while other very valuable 
materials were secured from the Museum of Comparative Zoology, through the kindness 
of Dr. S. Garman. As in former years, I have been indebted to Dr. Boulenger for some 
of the rarest forms. With all this the outlook has been greatly enlarged; but of course 
the results here reported are quite insignificant compared with those which will doubtless 
be attained, mainly by other workers, in the future. The whole subject is still in a pre¬ 
liminary stage, and when it is considered that the ideal program is no less than the exam¬ 
ination and description of the scales of every scaly fish, with figures of all the genera, it 
becomes evident that there is work ahead for an indefinite number of years. 
A few years ago an eminent European ichthyologist expressed the opinion that the 
detailed work on scales was a waste of time; for, said he, “We have other excellent 
characters on which to classify fishes, so why bother with scales?” Possibly this 
particular authority will never be converted to lepidology, but I do not believe anyone 
could spend much time in the minute study of scales without becoming convinced of 
their great value for purposes of identification and classification. Like all other struc¬ 
tures, they vary, and present characters of all degrees of significance and stability; in 
