Section IV, 1921 [93] Trans. R.S.C. 



A Supplementary Study of Panoplosaurus Minis^ 

 By Charles M. Sternberg 

 Presented by W. McInnes, LL.D., F.R.S.C. 

 (Read May Meeting, 1921) 



The genus and species Panoplosaurus minis was founded by the 

 late Mr. L. M. Lambe, F.R.S.C, Vertebrate Palaeontologist of the 

 Geological Survey of Canada.- But at the time of his death in 1919 

 he had completed only that portion of his descriptive work which 

 pertained to the skull and armature. 



The present article is intended to supplement that of Mr. Lambe 

 by descriptions of other portions of the type specimen (No. 2759, 

 \'ictoria Memorial Museum) than those dealt with in his paper. 



The writer is indebted to Mr. C. W. Gilmore, of the United 

 States National Museum, for reading and criticizing this paper. 



Vertebrae. — The total number of cervical vertebrae cannot be 

 stated as the posterior cervicals in the specimen are covered by the 

 dermal armature which it is not considered advisable to disturb. The 

 six anterior cervicals are well shown. 



The atlas and axis (Plate I, Figure 1) are fused, together and 

 resemble the corresponding elements in the Ceratopsia:' 



The atlas is long, broad and comparatively low. It is composed 

 of the centrum and neurapophyses firmly co-ossified, as are the other 

 cervicals, and the centrum is the longest of the neck series. It is 

 similar to the atlas oi Monoclojiius, as shown by Brown*, but differs from 

 that element in Scelidosaurns^ and Stegosaurus^. The anterior end 

 is deeply cupped and conforms to the shape of the occipital condyle. 

 The cup is sub-elliptical in outline w^ith the greatest diameter trans- 

 verse. The anterior superior border is notched. Both superior and 



1 Published by permission of the Deputy Minister of Mines. 



-' Transactions, Royal Society of Canada, 1919, Sec. IV, pp. 39-50, 12 plates. 



^ Monograph of U.S. Geol. Surv., vol. XLIX, by Marsh, Hatcher and Lull, 

 Figure 50. Bull. Amer. Mus. of Nat. Hist., vol. XXXVH, 1917, p. 288, by B. 

 Brown. 



4 Bull. Amer. Mus. of Nat. Hist., vol. XXXVH, 1917, p. 288, by B. Brown. 



5 A Monograph of the Fossil Reptilia of the Liassic Formation, by Owen, 

 Part H, Palaeontographical Soc, 1863. 



" U.S. Nat. Mus. Bull. 89, 1914, p. 45, by C. W. Gilmore. 



