138 PATAGONIAN EXPEDITIONS I PALEONTOLOGY. 



specimen consists of the carapace, nearly complete (Plate XVII) ; of the 

 skull (Plate XXVII), unfortunately without the mandible; of the dorsal 

 and lumbo-sacral tubes (Plates XXV, figs. 2, 3) ; nearly all of the tail ; 

 part of the scapula (Plate XXVI, fig. i) ; the humerus (fig. 2), radius, 

 pelvis, and femur. The absence of the mandible, the only known part of 

 the type, makes the reference to this species somewhat uncertain, but 

 there can be little doubt, I think, that this individual represents a species 

 distinct from P. australis ; that it belongs to Propalceohoplophorus is not 

 open to question. 



The carapace (Plate XVII) is 529 mm. long on the ventral border and 

 about 492 mm. on the median dorsal line, both measurements being taken 

 in a straight line, not following the curvature of the shell ; the transverse 

 width is greatest about the first movable band of plates and is here 378 

 mm. In the composition of the carapace and in the shape and ornamenta- 

 tion of its plates, no significant difference from P. australis is observable. 



Of the teeth (Plate XXIV, fig. 14) only A , * * and A are preserved, but 

 the shape of several of the others may be inferred from the uninjured 

 alveoli ; - is very small, transverse and of D-shaped cross-section ; - is also 

 small, with kidney-shaped masticating surface and non-lobate. The empty 

 socket of & shows that the division of the postero-external lobe was very 

 marked, much more pronounced than in the preceding species and ap- 

 proximating the condition of Cochlops. The same is true of -, which is in 

 place, and which is further characterized by the depth of the median verti- 

 cal groove of the anterior face, dividing the anterior prism into internal 

 and external lobes more distinctly than in P. australis. The last tooth, 

 *-, has a similar deep groove on the anterior face, but the postero-external 

 lobe is single. 



The skull (Plate XXVII), which is not quite complete, is yet remarkably 

 free from the distortion which has so altered and disguised the appearance 

 of most of the known glyptodont skulls from the Santa Cruz beds. It is 

 relatively small and of proportions quite notably different from those of 

 P. australis, as will be seen on comparing Plates XXIII and XXVII. 

 The most striking differences from the skull of the preceding species are 

 as follows : the whole skull is shorter and broader, with relatively more 

 elongate and wider cranium and decidedly shorter face ; the occiput is 

 both higher and broader and its crest much more regularly curved, the 

 margins of the foramen magnum are more prominent, giving the canal a 



