1U2 Transactions of the 



II. — On the Eevelopment of the Skull in the Genus Turdvs — 



the TJirushes. By W. K. Parker, F.K.S. 



(Bead before the Royal Microscopical Society, May 1, 1872*) 



Plates VIII., IX., and X. 



The Singing-birds, both as living creatures and as organisms, have 

 for many years exercised a sort of witchery over me, so that I am 

 always ready to give them my attention ; and they perhaps have 

 engrossed an undue share to themselves. There are plenty of 

 them ; the types of Passerine birds almost rival the fishes of the 

 sea in multitude ; and as to individuals, they are a prolific sort of 

 bird, and abound everywhere. Yet they are the highest kind of 

 birds, notwithstanding ; and in them the great Oviparous group, 

 called " Sauropsida," culminates. Amongst the cold-blooded groups 

 the Lizards come in most naturally for comparison with M carinate " 

 birds ; yet, morphologically considered, these are mere pupse as 

 compared with them. The particulars of conformity and of non- 

 conformity between these two great groups are of great interest, 

 and the genus here to be considered is important, in that, in one 



EXPLANATION OF PLATES VIII., IX., AND X. 



Plate VIII., Fig. 1. — Lateral view of skull of Turdus viscivorus, 3 or 4 days 

 before hatching, x 3 diam. 

 „ „ 2. — Lower view of ditto, X 3 diam. 



„ „ 3. — End view of ditto, x 3 diam. 



,, „ 4. — Fore-part of palate of same, X 9 diam. 



„ „ 5. — Hinder-part of lower view, x 9 diam. 



„ „ 6. — Same object, upper view, x 9 diam. 



„ „ 7. — Inner view of mandible of same, x 3 diam. 



„ „ 8. — Mandibular symphysis of same, seen from above, X 9 diam. 



„ „ 9. — " Cornu major " of " os hyoides " of same, x 3 diam. 



Plate IX., „ 1. — Lateral view of skull of Turdus merula, 1 day old, x 3 diam. 



„ „ 2. — Lower view of ditto, x 3 diam. 



,, „ 3. — Upper view of ditto, X 3 diam. 



„ „ 4. — End view of ditto, x 3 diam. 



„ „ 5. — Posterior part of basal view of ditto, x 6 diam. 



„ ,, 6. — Floor of cranium of same, seen from above, x 3 diam. 



,, ,, 7. — Part of end view of skull of same, unroofed, x 6 diam. 



,, ,, 8. — Mandible of same, inner view, x 3 diam. 



„ „ 9. — " Os hyoides " of same, x 3 diam. 



Plate X., „ 1. — Side view of skull (with mandible) of Turdus merula, 1 week 

 old, X 2 diam. 

 „ „ 2. — Lower view of ditto, X 2 diam. 



,, „ 3. — Upper view of ditto, x 2 diam. 



„ 4. — End view of ditto, x 2 diam. 

 „ „ 5. — Section of skull (with inner view of mandible) of the same 



X 2 diam. 

 „ ,, 6. — " Os hyoides " of same, x 2 diam. 



* It is but fair to state that, although this paper was read so long ago before 

 the Royal Microscopical Society, it did not pass into the Editor's hands till 

 Ftbruary 18, 1873. 



