140 
MEMO IBS OF THE QUEENSLAND MUSEUM. 
Pelorosaurus,' but if the centra figured by Hulke, previously mentioned, are 
congeneric, there is an extraordinary range of variation in structure — even 
for a sauropodous Dinosaur — in this genus. 
A. Smith Woodward, records : “ In Ornithopsis the centrum of each 
vertebra is chambered throughout, and the thin partitions between the small 
cavities consist of hard dense bone. 1 2 
In his jiaper, “ Zur Systematik unci Biologie der Sauropoden ” (1930) 3 
Baron Franz Nopcsa touches on the differential development of pleurocoeles , 
but he does not deal with the significance of an intramural complex of small 
cavities, and I can find no special references in Baron Huene’s papers. 
In Zittel’s Text-book of Palaeontology (Eng. Ed. 1902) only two families 
of Sauropoda, the Camarasauridse and the Diplodocidse, are recognised, whereas 
Marsh had previously recorded six. Four families are listed in " The Osteology 
of the Reptiles ” by S. W. Williston (edited by W. K. Oregon', 1925), with 
a long list of genera incertce sedis. Huene, however, lists six families in 1927 
(“ Short Review of the Present Knowledge of the Sauropoda,” These Memoirs, 
Vol. IX. pt. 1, 1927). He divides the Cetiosaurid® into two sub-families : 
" Cardiodontidae and Brachiosauridae,” and points out that the vertebrae of the 
latter are more cavernous than these of the former, although neither are so 
cavernous as in the families Morosauridae and Diplodocidse. It is doubtful 
whether the multiplication of families will tend to elucidate the phytogeny of 
this group. At present we have specialized genera such as Diplodocus in the 
Upper Jurassic with no known descendants in the Cretaceous, whilst, as 
R. S. Lull and F. Nopcsa 4 have pointed out, the comparatively simple type 
of Titanosaurus occurs in the Upper Cretaceous. 
As von Huene states, the natural classification of the Sauropoda is no 
yet clear. Doubtless our knowledge of their phytogeny will increase with 
new and more complete material. Where specimens are fragmentary the 
allocation of certain genera to families depends on the significance attached 
to certain features. As R. S. Lull points out, Barosaurus has several features 
in common with Diplodocus (including the two-branched characteristics of the 
chevrons, once thought distinctive), yet these are placed in distinct families. 5 
Notwithstanding the striking similarity between the intramural complex 
of the centra in Austrosaurus and Diplodocus, this Queensland Cretaceous 
1 Mantell, G. A., Phil. Trans. Boy. Soc., 1850, p. 379. 
2 Woodward, A. Smith, P.Z.S., 1905, p. 232. 
3 Nopcsa, F., Pateobiologica, iii.. Band, 1930. 
4 Nopcsa, F., Quart. Jown. Geol. 8>oc., I ol. LNNIN., 1923, p. 10/. 
6 Lull, B. S„ Mem. Connect. Acad. Vol. VI., 1919, p. 40. 
