ELEMENTARY SKETCH OF THE OSTEOLOGY OF BIRDS. 5 



which indicate the original boundaries between the supra- 

 and ex-oecipitals. Anteriorly the basi-occipital (b.o.) may be 

 seen to be produced into a long pointed style running along the 

 base of the skull, the anterior portion of which is termed the 

 sphenoidal rostrum* (sph.r.) Between this sphenoidal rostrum 

 and the basi-occipital there is really intercalated another bony 

 elementvrhicheovresponds to the basi-sphenoid (b.sph.) of mam- 

 mals ; anchylosis, however, has entirely obliterated the ori- 

 ginal divisions between these bones. The sphenoidal rostrum is 

 considered to be the representative of the parasphenoidf of 

 reptiles, — a bone which is not found in the mammalian 

 skull. 



The lateral border of the hinder portion of the palatal as- 

 pect of the skull is formed on either side by a slender bony rod 

 (pi. II q.j.)> which is mainly composed of two elements, the 

 quadrato-jugalX (q. j.) posteriorly, and the jugal^ (j.) anteri- 

 orly ; the second of these bones corresponds to the cheek-bone 

 (jugal) of man and other mammals, while the former is unrepre- 

 sented in the mammalian skull. On its inner aspect the quadrato- 

 jugal style posteriorly presents an articular facet which fits loose- 

 ly into a hollow of the quadrate^ bone (qu.) The latter bone is 

 somewhat square-shaped inferiorly ; while superiorly it forms a 

 flattened plate giving off two processes, one of which is directed 

 upwards and inwards towards the orbit, while the other j which 



* Sphenoidal rostrum, and basi-sphenoid. The os splienoide of human anatomy (from 



'i^rjV a wedge, and £iOOS likeness, in allusion to its shape) was applied to a large 

 irregularly-shaped bone which occupies the base and sides of the human skull in front 

 of the occiput, and which extends upwards to the orbits. This bone was divided into 

 three portions, the body (forming the base of the skull in front of the basi-occipital) and 

 the greater and lesser wings, the latter transmitting the optic nerve. Subsequently, by 

 the light of Comparative Anatomy, it was found that the sphenoid really was a complex 

 bone, and that it consisted of two median and three lateral pairs of elements. The two 

 median elements were contained in the so-called body, and were named hasi-sphenoid 

 and jore-sphenoid {prcs, in front of) ; the two pairs of wings likewise each consisted of 

 a pair of elements ; the greater wings were called alisphenoids (a barbarous word 

 derived from the Latin ala a wing, and S<^^>' ) while the lesser wings, as being con- 

 nected with the orbit, were termed orhito- sphenoids (also a barbarous word, derived 



from the Latin orhis, the socket of the eye, and S^W ). The other two bones, forming 

 part of the so-called sphenoid, were called pterygoids, and will be again noticed 

 below. 



The reader unacquainted with human anatomy will, perhaps, find some difficulty 

 in following the above ; but it is not of much importance in bird osteology, and it 

 will be better, when the various sphenoidal bones are named in reference to the bird 

 skull, to take them as abstract terms, without caring much for their original derivation. 



t Para-sphenoid ; Trapa, by the side of, and sphenoid. 



j See note 11 . 



§ Jugal, from jugum, a yoke, so named because this bone in man unites two pro- 

 jecting processes of the maxilla and squamosal {vide infra,) 



II Quadrate, from os quadratum, the " square-shaped bone ;" a bone connecting 

 the lower jaw of birds and reptiles with the skull, and so named from its shape. The 

 aame quadrato-jugal indicates a bone connecting the quadi'ate with the jugal. 



