366 Rev. H. N. Hutchinson — Observations on 



of this new reptile, Gigantosaurus by name, at 150 feet ! This 

 discovery, we think, tends to confirm the above argument with 

 regard to Diplodocus, its tail and its general pose ; for the larger the 

 reptile the greater the pull of its tail on the pelvic region, to say 

 nothing of the strain on the legs. Besides, mathematicians now tell 

 us plainly that there are certain physical limitations to the size of 

 a terrestrial animal (see recent discussions in Nature). 



By articulating limbs vertically, Hatcher and others have made 

 a kind of mongrel animal, part reptile, part mammal. Nature does 

 not mix her types; so Diplodocus must be either reptilian or mam- 

 malian ; it cannot be both. Its upright limbs are an anomaly. 

 Mammals are swifter of foot than reptiles. The mammalian skeleton 

 is constructed for speed, and is in every way adapted for upright 

 limbs. The pectoral and pelvic girdles are adapted to such limbs. 

 This is seen most conspicuously in the humerus and the femur. 



Articulation of the Vertebral Column. 



A few years ago the writer, in a visit to the Berlin Natur-Kund 

 Museum, had the opportunity of discussing the Diplodocus skeleton 

 with Dr. Brauer of that Museum. He is among those who do not 

 accept the interpretation of Diplodocus as represented by the skeleton 

 in London. And with regard to the tail, he brought forward an 

 argument which, as far as the writer is aware, has not been satis- 

 factorily answered. It is this: that several of the early caudal 

 vertebrae have been forced into unnatural positions, as shown by the 

 curious angular gaps between them. This can be distinctly seen in 

 the London specimen. But in the restored skeleton of Dr. W. J. 

 Holland's Memoir on the Osteology of Diplodocus, Marsh (Memoirs 

 Carnegie Museum, vol. ii, No. 6), there is no sign of this want of 

 harmony in the arrangement of the caudal vertebrae. 



The present writer has also noticed that a good many of the 

 vertebrae a little below those just spoken of show an entire want of 

 contact between the surfaces of the pre- and post-zygapophyses. 

 One would think that facts such as these might be sufficient in the 

 minds of unprejudiced naturalists to settle the question of the slope 

 of the tail, etc. But no ! the American palaeontologists wished this 

 great reptile to be as tall as they could make it. It has been 

 shrewdly pointed out by Professor S. "W. Williston of Chicago, lihat 

 in Diplodocus, as set up in our Natural History Museum, the position 

 of the tail is such as to make the extrusion of an egg an impossibility! 

 It is not easy to conjecture what answer will be made to this 

 objection by other Transatlantic naturalists. 



Supposing, as is likely, that Diplodocus was partly aquatic in 

 habit and sought his food in the waters of rivers and lakes, one can 

 well imagine that such a long tail would be useful by way of 

 balancing the body, and especially so if at times the body was raised 

 up to bring the head and neck up to the surface of the waters 

 for respiration. Professor H. F. Osborn put forward this view in 

 1899 (Scieiice, n.s., vol. x, No. 259, pp. 870-4, December 15, 1899). 



But he evidently stretches this view too far in the sketch of 

 a model of Diplodocus standing on its hind-legs, published in the 



