OP A MEGALANIAN GENUS PROM LORD HOWE’S ISLAND. 
477 
proportion of the margin of the articular concavity of the centrum, not continued 
upon the parapophysis, is sharply defined ; this articular surface is 1-g- inch by 1 inch 
2 lines. 
In Part III., c Phi]. Trans./ 1881, vol. 172, portions of the dermal skeleton, with 
productions meriting the name of “ caudal horns,” were described and figured. 
Meiolania repeats, with modifications, these characters of Megalania. 
An. osseous sub-cylindrical sheath, with similar defensive processes, was brought to 
light in one of the blocks of matrix forming part of the series of fossils from Lord Howe’s 
Island (figs. 3 and 4, Plate 31). To get clear demonstration that this sheath included 
vertebrae, a portion was removed, and careful detachment of inclosed matrix brought 
to light caudal centrums, one sufficiently well preserved to show the elongate sub- 
cyliudrical shape of the vertebral body, and the reduced area of the neural canal 
overarched by a simple thin bridge of bone. The three segments, subjects of 
fig. 3, consist each of an exo- and endo-skeleton. The former, x, x, is a cylinder, 
2-g- inches long, with an upper and a lower lateral pair of obtuse processes, d, d'. The 
thickness of the sheath varies from 2 mm. to 10 mm., the interspace between it and 
the included vertebra varies from 13 mm. to 3 mm. The osseous processes may have 
supported horny sheaths. The tail was relatively as long, probably, as in the Moloch 
Lizard (Plate 37, fig. 9, ‘ Phil. Trans.,’ 1880); and, as in that surviving representative, 
the terminal segments ceased to develope caudal horns. A portion of this part of the 
tail is the subject of fig. 4, Plate 31. The endo-skeleton, reduced to the vertebral 
centrums, is partially exposed. 
A singular appendage this long and seemingly inflexible tail must have been in the 
living Meiolania, contrasting with that part of the frame in the Chelonian order, 
whilst the edentulous modification at the opposite end of the body resembled that of 
the Tortoises and Turtles. The greater and closer affinity to the Saurian section of 
Peptilia is manifested by the vertebrae and parts of the limbs which have been brought 
to light. 
The portion of scapula includes the glenoid cavity, a little mutilated at the margin, 
and part of the expanded body or blade ; the “ neck ” supporting the cavity is well 
marked. The breadth of the preserved portion of this bone is 4 inches, the opposite 
diameter is 2 inches. The absence of any trace of suture between the blade and neck, 
or in the articular cavity, precludes a reference of the fossil to a coracoid. 
The portion of humerus includes the expanded proximal end, the shaft supporting 
which has undergone fracture ; this discloses a large medullary cavity, the wall varying 
from 5 to 3 mm. in thickness. Though fragmentary, this fossil is acceptable as testi¬ 
fying to a terrestrial stage of active life. 
In a former memoir * was noted the coalescence of the centrum and neural arch of 
a trunk vertebra ;t and in the series of comparisons with the spinal column in other 
* “Description of Remains of Megalania prisca,” Part II., ‘ Phil. Trans.,’ 1880, vol. 171, p. 1037. 
t P. 1038. 
