1896.] ON THE MYOLOGY OF RODENTS. 159 
CoNCLUSION. 
I do not feel justified in attempting to draw any general con- 
clusions as to the relations of the various divergences from the 
common type that I have described; but I think that I have 
brought together enough matter to show that when a much larger 
number ot facts has been collected, the method of investigation I 
have been following may furnish another clue to that riddle of 
zoology, the classification of birds. But in addition to this systematic 
interest, the comparative anatomy of a group of creatures so large in 
numbers and so alike in anatomical structure offers a field for the 
investigation of the innumerable divergences and convergences 
that have taken place in the evolution of the group. I cannot see 
that interpretations of isolated characters have any value. When 
we know the comparative anatomy of the greater number of 
characters that make up an animal, and not only those that seem 
to distinguish it as a species, the time may come for interpre- 
tation. But to those who care for discussions concerning isolated 
characters, I may suggest the problem: in these loopings of the 
gut in birds, there is an almost kaleidoscopic variety, and appa- 
rently these varieties are of systematic value; what are their 
utilities ? 
4. Myology of Rodents.—Part II. An Account of the 
Myology of the Myomorpha, together with a Com- 
parison of the Muscles: of the various Suborders of 
Rodents. By F. G. Parsons, F.R.C.S., F.Z.S., F.L.S., 
Lecturer on Comparative Anatomy at St. Thomas’s 
Hospital. 
[Received December 14, 1895.] 
The present paper is intended to be a second instalment to the 
one “On the Mvology of the Sciuromorphine and Hystricomor- 
phine Redents,” which I had the honour of reading before this 
Society in 1894 (see P. Z. S. 1894, p. 251). I am again indebted 
to the kindness of the Society’s Prosector, Mr. F. E. Beddard, for 
a large proportion of my material; indeed, it was his suggestion 
that a detailed examination of the muscles of Rodents would be 
of practical value in the Dissecting-Room at the Gardens that 
determined me to undertake the work in the first instance. 
The first part of this paper contains an account of the muscles 
of thirteen Myomorphine Rodents, and as a statement of actual 
facts will, I hope, prove of some value. 
The second part is devoted to a series of summaries and 
generalizations founded upon the facts with which these and 
previous dissections have furnished me. This part I regard as of 
less value than the first, because future dissections may make 
many alterations necessary. It seems well, however, to take 
stock of the mass of material from time to time as it accumulates. 
