CONTRIBUTIONS FROM THE ZOÖLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOÖLOGY AT HAR- 
VARD COLLEGE. E. L. MARK, Director. No. 166. 
THE SKATE AS A SUBJECT FOR CLASSES IN 
COMPARATIVE ANATOMY; INJECTION 
METHODS. 
HERBERT W. RAND. 
THE selection and obtaining of material for the laboratory 
work of classes in zoölogy, and the best methods of treating 
that material, are matters of considerable importance to those 
having such work in charge. My use of the skate for several 
years past has impressed me with the belief that it is, in some 
respects, peculiarly adapted for use in the laboratory work of 
classes in the comparative anatomy of vertebrates. If I am not 
mistaken, the advantages of the skate for this purpose and the 
practicability of using it are not always fully realized, especially 
by teachers who are situated at some distance from the sea. In 
view of this fact, I think it worth while to call attention to cer- 
tain points wherein the skate seems to me to be a superior sub- 
ject for laboratory work. In addition, I shall consider methods 
of injecting the circulatory system of this fish. 
If a student in comparative anatomy is to study a fish as 
a representative of the class, obviously it should be one which 
exhibits as nearly as possible primitive vertebrate conditions, — 
therefore an elasmobranch. If an amphibian is to follow the 
fish, it should, of course, be one of the tailed amphibians rather 
than the highly specialized frog. The elasmobranch, in its gen- 
eral anatomy, is much more directly and closely comparable with 
the urodele than is any teleost. To start a student in verte- 
brate anatomy on the dissection of a teleost and to follow that 
with the frog, as a representative of Amphibia, is as poor a pro- 
gram as could be arranged, if it is the intention that he should 
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