804 
ME. W. K. PAEKEE ON THE STEUCTUEE AND 
the characters of the Sand-grouse and Hemipod stood out before me. Rubbing these 
away, in my downward work the form of the Tinamou looked me in the face ; then the 
aberrant Ostrich seemed to be described in large archaic characters; a little while, and 
these faded into what could just be read off as pertaining to the Sea-turtle*; whilst, 
underlying the whole, the Fish in its simplest Myxinoid form could be traced in mor- 
phological hieroglyphics. 
I have but little used the suggestions of comparison, which have almost been burden- 
some at times ; but other monographs must follow ; and that of the Osseous Fish, which 
I hope to offer next, will show how gentle and gradual are the metamorphic changes by 
which the skull and face of a Vertebrate animal grow into harmony with the most 
diverse conditions and habits of life. 
Description op the PLATEsf . 
PLATE LXXXI. 
First Stage. — Head of Embryo, from bealc to occiput, 3 lines long : 
Mil Hay of Incubation. 
Fig. 1. Under view of head, x 9 diameters. 
Fig. 2. Upper view of basis cranii. X 9 diameters. 
Second Stage. — Head 4 to lines long : bth to Ith Hays of Incubation. 
Fig. 3. Vertical section of skull and face of an embryo with head 4 lines in length. 
X 6 diameters. 
Fig. 4. Ditto, with brain removed, of an embryo with head 5 lines long. X 6 diameters. 
Fig. 5. Side view of same. X 6 diameters. 
Fig. 5a. Part of the last (auditory region). X 16 diameters. 
Fig. 6. Section of the same through nose and palate. X 12 diameters. 
Fig. 7. Part of the last section. X 160 diameters. 
Fig. 8. Floor of skull, from above, of a somewhat older embryo. X 12 diameters. 
* Professor Huxley suggests that it was most probably the Bhynchosaurian Lizard, and not the Sea-turtle, 
which appeared to me in my observations on that stage. It is well worthy of remark that what Dr. Gunther 
(Phil. Trans. 1867, p. 599, Plate xxvr. fig. 2) has shown to be peculiar in Hatteria (a modern Bhynchosaurian), 
namely the articulation of the pterygoids with the vomers, is normal in the young Bird ; in most of the Orders 
the “ mesopterygoid,” which is at first a mere extension forwards of the pterygoid, articulates with the corre- 
sponding vomerine fork ; thus the palatines are thrust aside from each other, and from the mid line. This 
being the case, there is no difficulty about the separated palatines of Hatteria (see Dr. Gunther's note to p. 599 ) ; 
for separated palatines coexist with distinct palato-maxillaries in certain Birds — for instance, in Emberiza and 
Cardinalis. 
f The cartilage is tinted of a lilac colour, and the cartilage-bones ochre-yellow ; the membrane-bones and 
fibrous tracts are not coloured. \ 
