GIGANTIC LAND-LIZARD FROM AUSTRALIA. 
551 
the margin of the under surface of the tail. On this part may be distinguished some 
still smaller spines, with a scattered arrangement. 
At the under surface of the basal part of the tail the horns (b, c, cl) appear as shown 
in fig. 6, the surface is flattened and finely tuberculate but without spines. Towards 
the hinder half of the tail the two horns of the lateral pair deviate from the transverse 
parallel arrangement, and assume a zig-zag one, but with longitudinal intervals in 
proportion to their gradually decreasing size : the dorsal spines longest retain their 
liorn-like proportions. 
Moloch horridus thus exemplifies a closer resemblance in the number and arrange¬ 
ment of the annular series of caudal horns to Megalania than does Uromastix princess, 
and a closer repetition also in the shape and proportions of the individual horns : they 
are not compressed, but are more regular cones than in the Zanzibar Lizard. If the 
apex of the cone be sharper in Moloch than in Megalania, such difference may be due, 
as before remarked, to the absence of their corneous covering in the massive bony cores 
exemplified in the fossils from “ King’s Creek.” 
It is probable that the arrangement of these singular caudal weapons in the part of 
the tail of Moloch, which part is wanting in our present evidences of Megalania, may 
indicate the character of the armature of such missing evidences. But that the tail in 
Moloch is different at its terminal portion from the corresponding part in Megalania is 
demonstrable and not any of the homy cones have bony bases. 
For a repetition of so singular a structure we must go to a higher class of Ver¬ 
tebrates. Before, however, entering upon comparative details afforded by certain 
members of the Mammalian class, some further notice may be expected of dermal 
ossifications, more especially caudal ones, in the class Reptilia. 
In the group of existing Lizards to which both Moloch and Uromastix are akin 
there are genera, e.g. Scincus, Tiliqua, in which the scales, or most of them, are 
supported by bones : in Cycloclus the degree of ossification is such as to raise the 
surface of the skin both of the trunk and tail into prominences, which, however, are 
obtuse. 
The chief dermal ossifications in the order Chelonia form, as is well known, the 
horizontal plates which become confluent with the neural spines and pleurapophyses of 
the dorsal vertebrae ; also with the sternum and sternal ribs : the marginal plates of 
the carapace are independent skin-bones. But as no such ossifications are associated 
with the caudal vertebrae, further notice of these Reptilia is uncalled for in the present 
relation. A bony basis of the horny armour of parts of the tegument is constant in 
the species of the order Crocodilia. Along the dorsal and lateral regions, but espe¬ 
cially the dorsal, in the neck, trunk, and tail, the outer surface of certain of such 
scutes is produced into a ridge. In the Alligators ventral as well as dorsal scutes 
have an osseous support. This character is so remarkable in the extinct Crocodilia of 
the Oolitic period that the Teleosaur of the Caen deposits was characterised by Cuvier 
as “l’espece la mieux cuirassee de tout le genre.”'" 
* 4 Ossemens Fossiies,’ tom. v., pt. 2, p. 139. 
