Hector.—On the Fossil Reptilia of New Zealand. 339 
becoming thinner as they extended outwards, and also towards the fore and 
hind parts of the bone, both of which ends were broken away. On one side the 
surface of the bone is convex lengthwise, and slightly concave transversely, 
On the opposite side the contour undulates lengthwise, the surface being 
concave, then rising to a convexity, where a protuberance has been formed by 
part of the coadjusted mesial margins of the Бопе ; transversely this surface is 
slightly concave. А similar, but less developed, median prominence is seen at 
the middle of the medially united margins of the coracoids in the Plesiosaurus 
hawkinsii, and the author regards the above described parts of the New 
Zealand fossils as being homologous bones. But a more decided evidence of 
the Plesiosaurian nature of this antipodeal fossil is afforded by the vertebral 
centrums. They have flat articular ends, with two large and two small 
venous foramina beneath. The neurapophysial surfaces, showing the persistent 
independence of the neural arch, are separated from the costal surfaces by 
about half the diameter of the latter. These are of a full oval figure, 1 inch 
3 lines in vertical, and 1 inch in fore-and-aft, diameter. On one side of one of . 
the centrums the rib has coalesced with the costal surface. The following are 
the dimensions of this centrum :—Length 1 inch 9 lines, depth 2 inches 
9 lines, breadth of articular end 3 inches 6 lines. The non-articular part of 
the centrum offers a fine silky character."* 
To this same species I refer the specimens marked No. 15 and d in the 
collection of the Colonial Museum. 
No. là.—This consists of the thoracic segment of the trunk of a young 
individual The dorsal surface of the animal has been worked out of the hard 
matrix of the slab so as to expose ten posterior dorsal segments with ribs. 
No vertebral centra are exposed in sif, but scattered on the slab among the ribs 
are four belonging to the dorsal region, and about twelve to the caudal, together 
with the smaller bones of the paddles. The thoracic ribs, a few abdominal 
ribs, and the dislocated bones of the pelvic arch and appendages, complete the 
‘specimen, which measures 2 feet square. The matrix is the usual grey cement 
stone, containing an excess of lime, which is crystallized out in cracks, the 
vertebrz, for instance, being split through the neural spines by a thick vein 
of calespar that traverses the entire length of the column, and is continued so 
as to intersect the femur of the rigbt side. The neural spines project 
1-5 inches above the transverse processes. They have rounded tips, are 
1:3 inches in antero-posterior width, with zygapophyses projecting *4 inch. 
The transverse processes are 1-7 inches long, cylindrical, and of the same size as 
the ribs, to which they are attached without any expanded facet, either on.the 
process or the head of the rib. 
The ribs, which are directed backw ards on the spine as they lie in the 
* Owen, Proceedings of Brit, Assoc., 1861, p. 122. 
