350 



The vomer is carinate below. The nasals are distinct from each other and from the frontals : 

 they are grooved externally for the premaxillaries. The petromastoid, tympanic and temporal 

 bones continue permanently separate, though confluent ossification proceeds to blend the 

 occipital, parietal and frontal into one hone. The petrosal is small, its tentorial ridge or angle 

 is sharp, and its cerebellar fossa very deep, though small : a branch of the lateral sinus per- 

 forates the petromastoid and the adjoining part of the temporal to open behind the root of 

 the zygoma : the mastoid part is compressed and abuts against the outer side of the base of 

 the paroccipital. The tympanic is a simple scoop-shaped bone, or half-cylinder, cut obliquely. 

 The inferior turbinals are perforated like fine lace-work. The palatine process of the pre- 

 maxillary is very deeply notched, and is excavated behind the outer incisor. 



Presented by Ronald Gunn, Esq. 



1909. The detached bones of the skull of the very young, or mammary foetus of the 

 Thylacine (Thylacinus cynocephalus). They are numbered in accordance with 

 the TABLE OF SYNONYMS. Presented by Ronald Gunn, Esq. 



1910. The upper jaw and most of the teeth of a young Thylacinus cynocephalus. The 

 formative cell of the last molar is shown ; the crown of the penultimate molar 

 is protruding from the socket. Presented by Ronald Gunn, Esq. 



1911. The atlas vertebra of a Thylacinm cynocephalus. 



The bony circle is completed by the meeting of the neurapophyses below : the transverse 

 process, as well as the neural arch, are perforated by the vertebral artery. 



Presented by Ronald Gunn, Esq. 



1912. The axis vertebra of the same Thylacine. Presented by Ronald Gunn, Esq. 



1913. The remaining cervical vertebrae and first dorsal vertebra of the same Thy- 

 lacine. 



The parapophysial part of the transverse process is extended downwards in the last four 

 cervicals, and in the seventh it does not join the diapophysial part : this contributes, with 

 the diapophysis of the first dorsal, to form the articular cavity for the tubercle of the first rib. 



Presented by Ronald Gunn, Esq. 



