534 DR. R.W.SHUFELDI ON THE COMPARATIVE OSTEOLOGY [ Apr. 27, 
the Humming-birds would be quite unavailing. In all respects 
it is very different. I shall proceed, then, to complete this 
account with a description of the remainder of the axial skeleton 
and the skeleton of the limbs in Arachnothera, comparing the 
principal characters with those presented by the skeletons of the 
other families above-named. 
REMAINDER OF THE AXIAL SKELETON.—So far as the vertebre 
are concerned between the skull and the pelvic sacrum, the 
several families of birds here being considered are all strictly 
passerine in character. I have counted and compared them in a 
representative of each family, and am satisfied that these bones 
offer nothing worthy of an extended and detailed description. 
To be sure, we find some differences in form among the various 
species, genera, and families, but such characters are of but slight 
importance, and in all instances the variations are no more 
marked than those which obtain among more or less nearly related 
passerine birds in the avifauna of any country of great extent, 
as, for example, in Stalia, Wimus, and American Warblers, as 
compared with the Passeres of the Pacific Coast region*. Both 
Arachnothera magna and A. longirostris possess 19 vertebre 
between the skull and the pelvic sacrum; the first twelve are 
true cervical vertebree without free ribs. The 13th and 14th are 
also cervicals, the first supporting a pair of very small free ribs, 
and the last a far better developed pair, which are likewise free 
and without wnciform processes. The next five are true dorsals 
and possess these appendages, and also connect with the sternum 
through the intervention of costal ribs. We also find a very 
delicate pair of ribs attached to the leading vertebra of the 
sacrum, the sternal ribs of which are ‘floating ribs.” Dorsal 
vertebre have well-developed neural spines which are in contact 
with each other anteriorly and posteriorly, the ultimate dorsals 
being lacking in hemal spines. 
There are seven free caudal vertebre in the skeleton of the tail 
in A. magna, in addition toa rather large pygostyle. The form 
assumed by the latter is well-shown in the Plate illustrating this 
paper. In the family Meliphagide there appear to be but six 
caudal vertebre and the pygostyle, and this is likewise the case 
among the Ccerebide, as, for example, in Cyanerpes cyanea. 
However, we know that even in the same species these caudal 
vertebra may vary to the extent of one, or may be two; they are 
not constant even 1n our own species. 
As well as can be made out from an adult skeleton, or rather 
a skeleton from an adult individual, it would appear that there 
are eleven vertebre fused together to form the pelvic sacrum in 
* SuuretpT, R. W. “Contributions to the Comparative Osteology of the 
Families of North American Passeres.” Jour. Morph. vol. ui. no. 1, Boston, 
June 1889, pp. 81-114, pls. v. & vi. A large number of the passerine birds of the 
United States are osteologically compared in this paner. 
