130 R. Klheridfie : 



anterior end is wide transversely. The following are the principal 

 measurements : — 



inches. 



Length of centrum ...... 3 



Breadth of the same behind the ball - - - - If 



Vertical, or longitudinal, diameter of ball - - - l^- 



Transverse ditto ----... is 



Vertical, or longitudinal, diameter of centrum - - - If 



Pore and aft diameter of cup - - - - - 1^ 



Transverse diameter of cup - - - - - 1 1 



Transverse diameter of anterior outlet of neural canal - - | 



Transverse diameter of posterior ditto - . . . | 



The remains of Megalaiiia prisca, inclusive of Notiosaurus den- 

 tatiis, have now been found in fiuviatile, mound spring and cave 

 deposit, as follows : — 



Fhiviatile de^josits 



r Condamine Eiver and its branches (King 

 ) Creek, &c.), Queensland; "Near Melb- 

 y oume,"i Victoria; South Australia; 

 ' Castlereagh River, N. S. Wales. 



Mound Spring deposit - ^ C«ddie Springs, East of Gulgongong, 



(. N. S. Wales. 

 Cave deposits - - - Wellington Caves Reserve, N. S. Wales. 



3. — Lacertilian Dermal Armour. (PI. 8, Figs. 6-9). 



For two very interesting fragments from the Opal beds of Light- 

 ning Ridge, near Walgett, New South Wales, I am indebted to 

 Mr. T. Wollaston, of Adelaide. Both are formed of roughly hexa- 

 gonal bony pieces (PI. 8, figs. 6-8), firmly united by their margins 

 in alternate series. Each component plate is limpet-shell-shaped, 

 more or less, obliquely and unequally conical fore and aft, with 

 a backwardly projecting obtuse apex, with a tendency to overlap in 

 a similar direction. One specimen (PI. 8, figs. 6, 7) is composed of 

 six larger plates, with three smaller along one of its margins form- 

 ing, as it were, a border. The second specimen (PI. 8, fig. 8) 

 comprises five plates of a like nature, and again with three smaller 

 marginal pieces. 



These plates are thick, of a compact and bony tissue, the structure 

 of the latter displayed on the inner surface; externally they are 

 highly rugose, the rugosities papilla-like, and usually separate 

 from one another, but here and there becoming semi-confluent, with 

 the narrow interspaces between the papilla often pitted. When 



1 It would be iiiterestiiitr to know the exact locality. 



