in the Classification of Birds. 19 
when taken in connection with others. In some few birds 
Tunderstand, it is difficult to determine whether this area 
of origin is oval or triangular, but as a rule no such diffi- 
culty presents itself. For my own part it constitutes a dif- 
ference which, I am free to confess, I had as yet paid but 
little attention to, as for several years past neither the prop- 
er material nor other facilities for such investigations have 
been available. Nor am I quite suréin my own mind as 
yet, how far the form of the hinder portion of the pelvis 
may influence the origin of this muscle; and whether such 
birds do not exist wherein a large obturator internus is de- 
manded, and where their pelvesare short, in which cases 
the muscle, to gain a firmer origin, would naturally spread 
out posteriorly, and thus of necessity become triangular. 
But as I say, [am not prepared to pass final judgment 
on this matter, and render a personal opinion as to whether 
much reliance can be placed upon it as a useful character 
in determining affinities among birds. 
Here then again is a field open to decide an important 
point, and one easily to be understood, and not difficult to 
render extensive records about. Those living where land 
and water birds occur in abundance could soon determine 
whether (or no) this character possessed any taxonomic value 
or not, and the result would surely prove of service to 
ornithology. 
ON THE MUSCULATURE OF THE SYRINX. 
Research of a far more extensive character will have to 
be made in this direction before results can be attained, and 
data secured which can be generally used with effect in 
classification. Much of course is already known, as we are 
aware for instance, that in the true oscine type four or five 
pairs of intrinsic muscles are found associated with the 
syrinx, and these are inserted into the three upper bronchial 
semi-rings at their extremities ; hence these birds have been 
designated as the Passeres Acromyodi, and in them the 
syringeal apparatus is of a very complex nature, holding 
the highest place among birds as an organ of voice. On 
the other hand we have the Passeres Mesomyodi, or the 
