1905.] 0^" THE AXATOMY OF THE FRILLED LIZAUD. 9 



In front of the frontal bone, between it and the nasals, is a 

 squarish piece of bone distinct from both of these. In many 

 Agamidae there exists, according to Siebenrock, a fontanelle in this 

 region, and the same occurs in Iguana and Phrynosoma. It is, 

 however, according to Siebenrock, filled up in the full-grown lizard, 

 and thus a character of youth. The plugging up of the vacuity 

 by a separate bone in Uromastix, not mentioned by Siebenrock, 

 leads me to the inference that this bone is to be looked upon not 

 as a detached fragment of the frontal — a wormian bone, but as an 

 ossified mesethmoid comparable to that which exists upon the 

 surface of the skull in some Struthious birds. &c. 



2. A Contribution to the Anatomy of the Frilled Lizard 

 {Chlamydosaurus hingi) and some other Agcuinda\ By 

 Frank E. Beddard, M.A., F.R.S., Prosecutor to the 

 iSocietj. 



[Received November 29, 1904.] 



(Text-figures 5-10.) 



Except for its muscular anatoray, which has been described by 

 Mr. de V^is *, and for certain points in its osteology which have 

 been described by Dr. Mivart t and Prof. Dollo %, the structure 

 of the genus Chlamydosaitrus appears to be but little known, 

 though the external characters § and habits || have been studied 

 and recorded by many natviralists. The following pages contain 

 a contribution to our knowledge of this Lizard as compared 

 with allied genera among the Agamidse, of which family it is un- 

 doubtedly to be reckoned a member. 



Lungs. — Seeing that the lungs of the Lacertilia are evidently 

 capable of considerable variation *\ and that the habits of Chlamy- 

 dosaurus and Physignathits are very different, it is not remarkable 

 that their lungs show certain differences of structure. They 

 are, however, broadly similar and constructed upon a plan which 

 characterises the family Agamidfe — to which these two genera 

 belong — and the Iguanidse. This is seen in the fact that the 

 lung (both right and left) is divided into two non-communicating 

 compartments, only communicating — that is to say — indirectly 

 through each bronchus. - The tip of each lung which is continued 

 headwards beyond the bifurcation of the bronchi constitutes the 

 second and smaller compartment of the lung. This, however, 



* Proc. Linn. Soc. N. S. W. viii. 1883, p. 300. 



t Article " Reptilia," Encycl. Brit. 9th ed. 



X Rev. Quest. Sci. xix. p. 318. 



§ Gray in King's Survey of Australia, ii. p. 424 ; Dumeril and Bibron, Erpetol. 

 Gen. p. 440 ; Boulenger, Brit. Mus. Cat. ; Beddard, P. Z. S. 1904, vol. ii. p. 82, 

 Encycl. Brit. 9th ed., Article " Lizard." 



il Savile Kent, P. Z. S. 1895, p. 712. 



■|f Milano, " Beitrage z. Kenntniss d. Reptilienlungen," Zool. Jahrb. (Abth. f. Anat.) 

 vii. p. 545 ; he does not deal with either of the types described above. 



