PROGRESS IN VERTEBRATE PALAEONTOLOGY 4 57 



collection of Mr. J. Parker, of that city. In place of referring 

 this specimen to Megalosaurus, Baron Nopcsa considers that it 

 indicates a genus apart, which he identifies with Strcptospondylus, 

 typified by a few vertebrae and limb-bones in the Paris Museum 

 from the Kimeridgian of Havre. Among other peculiarities, the 

 Oxford dinosaur is stated to differ from Mcgalosaiirus in posses- 

 sing four (in place of three) hind-toes. It may, however, be 

 mentioned that Phillips, in his description of the typical species 

 of the last-named genus, stated that he was uncertain whether 

 there might not have been a fourth hind-toe. 



Before leaving the subject of dinosaurs, it may be mentioned 

 that American palaeontologists have recently attempted to 

 estimate the "live-weights" of Diplodocus and Brontosaurus. 

 Although the attempt might seem hopeless, their method of 

 going to work has been so thorough that there appears to be 

 considerable probability of the estimates presenting a fair 

 approximation to the reality. The plan adopted was to make 

 a model of the entire reptile, as deduced from a study of the 

 skeleton, on a scale of one-sixteenth the natural size. The cubic 

 contents of such a model multiplied by the cube of 16 would 

 indicate the probable amount of water displaced by the reptile 

 when in the flesh. To arrive at this result, one of the miniature 

 models of Brontosaurus (the length of whose skeleton is 66\ ft.) 

 was cut into six pieces of convenient size for purposes of 

 manipulation ; and the equivalent water-displacement of each 

 of these fragments determined. From this the water-displace- 

 ment of a model of the natural size was calculated by means 

 of the above-mentioned formula, which gave as a result the 

 displacement of 34^ tons by the entire animal. Since, however, 

 Brontosaurus is believed to have walked along the bottom of 

 lakes in search of food to depths which caused its whole body 

 to be submerged, it is probable that the reptile in life was 

 slightly heavier than water, and to allow for this an addition 

 of about 10 per cent, was made to the calculated weight, thus 

 bringing the estimate to a total of 38 tons. Vast as is this 

 weight, it is, however, only about two-thirds of the estimated 

 weight of the heaviest whales, which is presumed to be not less 

 than 60 tons. It may be added that the weight of the African 

 elephant " Jumbo " was only 6| tons. 



The Mesozoic crocodiles with amphicoclous vertebrae of 

 North America receive treatment in the American Journal of 



