PE(irESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA. 



547 



figs. 9, 10), the length of the centrum of which has been noted above, shows a breadth 

 of hind surface (fig. 10) of 5 inches 9 lines, its height being 4 inches; the antero-pos- 

 terior extent of the base of the pedicle is 2 inches 6 lines ; about 9 lines extent of the 

 centrum extends backward beyond it. 



The smaller pair of epiphysial vertebral plates (ib. fig. 12), cemented together by the 

 matrix, have come, according to their size and shape, from the cervical series ; they are 

 transversely elliptical, 4 inches 6 lines in long diameter, and 3 inches in short diameter. 

 The thicker free or peripheral margins (12, a) diverge from each other, and they thin off 

 to a central vacuity (12, c). The larger pair (ib. fig. 13) appear to be from the lumbar 

 series ; they measure 4 inches 7^ lines across, and 3 inches 8 lines down the middle ; 

 their central vacuity is transversely oblong, measuring 1 inch 3 lines by 1 inch. These 

 detached vertebral epiphyses are completely petrified. 



The terminal epiphyses of the bodies of dorsal and lumbar vertebrae remain distinct, 

 and come off in pairs attached by intervertebral substance in Kangaroos which have 

 arrived at full growth. I presume that the same circumstance occurred in the course 

 of decomposition or maceration of the carcass and skeleton of Diprotodon ; hence the 

 presence of such separate pairs of epiphyses receiving co-attachment from the matrix 

 after separation from their proper centrums*. 



Of the ribs, though few are entire, so many have reached me as suffice to show that, 



* Since the reception of the specimens of vertebrae above described, I have been favoured with two drawings, 

 of the natural size, of a side view and end view of a lumbar vertebra of a Diprotodon, from St. Euth's Station, 

 Condamine Eiver, Queensland, by Dr. Fe. Campbell. In these drawings sufficient of the neural arch is pre- 

 served to show the base of the diapophysis extending outward, at 1 inch 6 lines above the level of the upper 

 surface of the centrum. The breadth of the centrum is 5 inches, its vertical diameter 4 inches ; the breadth of 

 the neural canal is 3 inches 6 lines, the fore-and-aft extent of the centrum at its upper third is 2 inches 10 lines. 

 An oblique broad low ridge or rising of the outer surface of the pedicle rises to the lower part of the base of the 

 neurapophysis. 



The two drawings, of side and front views, of this vertebra have been made carefully, and I believe accu- 

 rately, as regards admeasurements, by Mr. Campbell's son, who found the vertebra, and whose letter to his 

 father on the subject is as follows : — 



(Copy.) 



" St. Euth, 25th May, 1865. 

 " The enclosed drawings I send to you to amuso you a little till I come down, speculating as to what the huge 

 animal was. I have the boue and some more, now in my possession. A large top jaw with a few pieces of 

 teeth sticking in it, and what looks like a blow-hole in the top — some smaller shank bones, or something of the 

 sort — all fossil. They ring like cast iron when knocked together : too heavy to bring down with me : — they 

 arc of a dark brick colour. I will try and make drawings of the rest if I have time before I come down. One 

 of the vertebrae of a Bull looks very small indeed alongside this great bone. 



(Signed) " Hugh Campbell." 



In the letter inclosing his son's drawings Dr. C. vmtes : — " The bones he mentions ui the letter and whose 

 likeness is also inclosed herewith, I regret to say he was induced to part with to a gentleman to whom he was 

 under particular obligations of friendship, and who had expressed a great desire to possess them." Should the 

 present notice ever meet the eyes of the possessor of these fossils he may be assured that it would give me 

 pleasure to make them subservient to the advancement of a knowledge of Diprotodon. 



