ON CERTAIN STORKS. 421 
67. NOTE ON AN ANATOMICAL PECULIARITY IN 
CERTAIN STORKS.* 
Tue Ciconiide, whilst presenting great uniformity in their myology, Page 711. 
differ among themselves in one feature which seems to me to be of 
sufficient interest to deserve special record, as it may aid those who 
study their external characters to arrive at a more satisfactory deter- 
mination of their affinities among themselves. 
The following are the species I have had the opportunity of dis- 
Ciconia nigra. Xenorhynchus australis. 
— alba. senegalensis. 
— boyciana. Leptoptilus crumeniferus. 
—— maguari. argala. 
Abdimia sphenorhyncha. Tantalus ibis. 
In all these birds, with the exception of Abdimia sphenorhyncha 
and Xenorhynchus senegalensis, I have found the ambiens muscle, 
which courses obliquely through the front of the capsule of the knee, 
present, although never large; whilst in the two last-named birds, Page 712. 
both from Africa, it is absent on both sides of the body. Such being 
the case, it seems to me highly probable that the relationship between 
_ Abdimia sphenorhyncha and Xenorhynchus senegalensis is more intimate 
than that between X. senegalensis and X. australis; and this view is 
favoured by their geographical distribution. 
The tendency of the ambiens muscle to vanish in certain of the 
birds so closely allied as the Storks under consideration, in certain 
Psittaci, as well as in some of the Columbe, is one which our know- 
ledge of their habits does not enable us to explain. It can have no 
relation to the habits or bulk of the species; for this muscle is present 
in the Ostrich as well as in the smallest Cuckoo, whilst it is absent in 
the Cassowaries and the Passeres. The fact that it is not found in 
certain Storks makes its total loss in ee Ardeidz less surprising than 
it would otherwise be. 
* “Proceedings of the Zoological Society,” 1877, pp. 711, 2. Read, Nov. 6, 
1877. 
eT 
