693 

 4390. The skull and atlas of a male Dingo (Canis Dingo). 



Like the Jackal and Wolf, the Dingo differs from the Fox in the greater transverse convexity 

 of the frontals, especially opposite the postorbital processes, and in the greater longitudinal 

 depression between the frontals ; in the greater posterior extension of the nasals, as compared 

 with the maxillaries ; and in the encroachment of the lacrymal bone upon the face. An in- 

 teresting exemplification of characters of affinity, as contrasted with those of adaptation, is 

 afforded by a comparison of this skull with that of the Marsupial Carnivore (Thylacinus Har- 

 risii) from the same part of the world, which equals the Dingo in size, agrees with it in 

 general outward form, and has similar habits, food, and mode of life. 



The first and most striking difference is the comparative superiority of the cerebral cavity 

 in the Dog, and of the olfactory cavity in the Thylacine, the proportions being reversed in 

 the two specimens. The superoccipital overhangs the foramen magnum in the Dog, but is 

 on the same vertical plane with it in the Thylacine. The paroccipitals are more compressed 

 in the Thylacine, and their base is not applied to the acoustic bulla, which is of much smaller 

 size and formed exclusively by the alispheuoid, not by the petrosal and tympanic, as in the 

 Dog. The tympanic has preserved its distinctness in the Thylacine, but has coalesced with 

 other elements of the temporal bone in the Dog. A wide and deep groove divides the bulla 

 from the basisphenoid in the Thylacine, but the sides of the basisphenoid in the Dingo are 

 swollen and abut against the large tympanic bullae. The articular cavities for the lower jaw 

 are much nearer the occiput in the Thylacine than in the Dingo, and the malar bones enter 

 partially into their formation. There are two large vacuities in the back part of the bony 

 palate in the Thylacine, but this part is entire in the Dingo. The antorbital foramina are 

 larger in the Thylacine and much nearer the orbits than in the Dingo ; they are also formed 

 partly by the malar, and are not wholly perforated in the maxillary bone, as in the Dingo : 

 the lacrymal bone is much larger in the Dingo, and encroaches much more upon the face : 

 the nasal bones are broader posteriorly in the Dingo, and extend further back, as compared 

 with the maxillaries. The calvarium has been removed from the two specimens compared 

 (Nos. 1905 and 4390), to show more distinctly the different proportions of the cerebral and 

 olfactory cavities : the petrosals are much larger in the Dingo, and send bony plates into the 

 tentorium, which plates are not present in the Thylacine. The sella turciea is defined by the 

 posterior clinoid processes in the Dingo, but not in the Thylacine. The foramina optica and 

 lacera anteriora are blended together in the Thylacine, but are distinct in the Dog. Although 

 the olfactory chamber is so much larger in the Thylacine, the rhinencephalic fossa is smaller 

 than in the Dog. The lower jaw, besides its greater length and slenderness hi the Thylacine, 

 differs by the bending in of the angle, which is the characteristic of the Marsupials. In 

 most of these distinctions the Thylacine manifests its nearer affinity to the oviparous type of. 

 skeleton. The difference in the dental formula is more decisive than the osteological ones ; 

 but in the greater number, and the greater conformity of shape of the molar teeth of the 

 Thylacine, there may also be discerned a greater conformity with the inferior type of verte- 

 brate organization. 



Presented by Governor Sir George Grey, C.B. 



