176 MR. W. K. PARKER ON THE OSTEOLOGY 
recently hatched Corvine, Turdine, and Sylviinz, and is extremely unlike that of the 
Galline, Columbine, Pluvialine, or Struthioninz. 
The fossa in front of the condyle is well defined in the Hemipodius ; but the anterior 
and posterior condyloid foramina, and the passage for the ‘‘ vagus,’”’ are very small 
(Pls. XXXIV. & XXXV. figs. 1, 8,9). The ‘‘basitemporal” region (.t.) is in size and 
shape intermediate between that of the Pigeon (Pl. XXXVII. fig. 6) and Lapwing 
* (Pl. XXXVIL. fig. 1) ; and its anterior lip, below the common opening of the Eustachian 
tubes, is less pronounced than in the latter, but more than in the former. In the Lap- 
wing it is really a well-defined process, whilst in certain of the Anatine it is a sharp 
style. 
Where the large external ala of the basitemporal’ meets the most anterior spur of 
the lateral occipital, it bridges over an empty space a little external to the foramen for the 
vagus.” In this the Hemipodius agrees with the majority of birds. A line or so in front, 
and mesiad of this space, is the opening of the elegant bony canal for the internal carotid 
(Pl. XXXIV. fig. 1, i.c.), which canal, principally formed by the basitemporal on each 
side, yet owes some of its substance above to the basisphenoid, and internally (as in the 
mammals) to the petrosal (prootic). Rathke erroneously terms the symmetrical bones, 
which in the Snake, Lizard, and Bird invest the internal carotid artery, basisphenoid ; 
whilst the true basisphenoid, formed originally by ossification of the cartilaginous 
pituitary floor, he calls ‘‘ presphenoid”’ (see Mem. on Baleniceps, p. 280). In my 
former paper (p. 316) I spoke of having found the rudiment of a true tympanic bone in 
the Peahen. Since that time I have dissected a large number of the skulls of growing 
birds, and find that in one form or another it is a very constant element in the class of 
birds, oftener, however, existing as a series of ossicles than as one distinct ring*. The 
bird-class is indeed remarkable for a free development of bony centres, every available 
structure being in some species converted into bone. We shall see a remarkable in- 
stance of this in the case of the Tinamou ; but even in such highly organized birds as 
the Falconing, where the growth is so rapid, and the coalescence of bony elements so 
complete, there is a profusion of separate pieces, even where their distinctness is most 
transitory. Let the mere ‘‘ teleologist,” the anatomist of the Sir Charles Bell school, 
look well to this ! * 
+ The basitemporal of birds, being very large, ossifies the ‘‘ lower tympanic lip” of the periotic capsule. 
* Miiller (Physiology of Man, Baly’s transl. 1843, vol. ii. p. 1616) says:—‘ In young mammiferous animals 
two other parts”’ (besides the os quadratum and os zygomaticum) “ can be distinguished in connexion with the 
temporal bone, namely the annulus tympanicus and the bulla tympani, which Hagenbach could distinguish as 
separate parts in some mammals.”” Platner saw “an annulus tympanicus in several birds ; and frogs have also a 
rudiment of the same part.’ The ossification of the true internal “ bulla tympani” is continuous with that of 
the prootic in most mammals ; this lower lip of the primary cartilaginous tympanic wall is often absorbed. It 
is well developed in the Hyrax and Sloth. 
8 [shall not pass by this part of our subject without giving an instance of the prejudices of our anatomical 
fathers against the results of embryology. 
The great man just mentioned, whose writings have been the joy of every lover of biology, takes occasion, in 
