marsh.] DISTRIBUTION OF SAUROPODA. 185 



of the smaller species of Morosaurns, but indicate an animal of slighter 

 and more graceful build. The metapodials are much more slender and 

 tlie phalanges are less robust than in the other members of the order, as 

 shown in Pi. XLI. 



DISTRIBUTION OF THE SAUROPODA. 



In the preceding pages the most important forms of the Sauropoda 

 now known from North America have been briefly described and illus- 

 trated. The only remains known from other parts of America are a few 

 fragmentary specimens recently found in Patagonia, and described by 

 Lydekker, under the generic names Argyrosaurus and Titanosaarus, 

 in the Anales del Museo de La Plata, 1S93. The specimens now known, 

 although in poor preservation, show distinctive characters of the order 

 Sauropoda, and indicate reptiles of gigantic size. The discovery is 

 interesting and will doubtless soon be followed by others of more 

 importance. 



In England remains of Sauropoda have long been known, and the 

 first generic name given was Cardiodou, proposed by Owen, in 1841, and 

 based on teeth alone. A number of other generic names have since 

 been proposed, and several are still in use, Among these are Cetio- 

 saurus and Bothriospondylus Owen, Pelorosaurus Mantell, iEpysaurus 

 and Hoplosaurus Gervais, Ornithopsis Seeley, and Eucamerotus Hulke. 

 The absence of the skull, and the fact that most of the type specimens 

 pertain to different parts of the skeleton, render it difficult, if not impos- 

 sible, to determine the forms described, and especially their relations 

 to one another. 



COMPARISON WITH EUROPEAN FORMS. 



In examining the European Sauropoda with much care the writer 

 ■was impressed by three prominent features in the specimens investi- 

 gated : 



(1) The apparent absence, of any characteristic remains of the Atlau- 

 tosauridffi, which embrace the most gigantic of the American forms. 



(2) The comparative abundance of another family, Cardiodontidas, 

 nearly allied to the Morosauridre, but, as a rule, less specialized. 



(3) The absence, apparently, of all remains of the Diplodocidse. 



A number of isolated teeth and a few vertebras of one immature indi- 

 vidual appear to be closely related to the Pleuroccelidaj, but this, for 

 the present, must be left in doubt. 



A striking difference between the Cardiodontidfe and the allied Amer- 

 ican forms is, that in the former the fore and hind limbs appear to be 

 more nearly of the same length, indicating a more primitive or general- 

 ized type. Nearly all the American Sauropoda, indeed, show a higher 

 degree of specialization than those of Europe, both in this feature and 

 in some other respects. 



The identity of any of the generic forms of European Sauropoda 

 •with those of America is at present doubtful. In one or two instances 

 it is impossible, from the remains now known, to separate closely allied 



