206 Prof. li. Owen on the Occurrence 



in length and twelve in transverse diameter, and that one of 

 the dorsals measures three and a half feet in the spread of its 

 diapophyses, two and a half feet in elevation, and the centrum 

 thirteen inches in transverse diameter " *. 



From the numerous and close agreements demonstrable 

 between my "anterior trunk- vertebra " and Prof. Cope's 

 " supposed cervical vertebra," I am quite prepared to receive 

 from our submerged Wealden deposits of the Isle of Wight a 

 dorsal vertebra rivalling the dimensions of the Dakota one, in 

 the ratio of 1 foot 3 inches to 1 foot 8 inches, which differen- 

 tiates the dimensions of the more advanced vertebree compared. 

 But that so rich an accession of illustrations of this probably 

 " largest or most bulky animal capable of progression on 

 land " t as the Dakota rocks have revealed at their out- 

 crop, should be extracted from the resting-place of the British 

 giant, would be an event that I cannot flatter myself that I 

 shall contemplate during the brief remnant of my working 

 days. 



Concluding, from the seven characters assigned in the mono- 

 graph of 1876 to Chondrosteosaurus, that the remains from 

 Dakota, affording their describer the same seven characters, 

 are of that genus and probably of the same species, tlie addi- 

 tional elements toward its reconstruction brought to light by 

 Mr. Lucas and described by Prof. Cope constitute a most 

 acceptable and interesting accession to the knowledge of ex- 

 tinct Reptilia. 



In Prof. Cope's ' Palgeontological Bulletin,' no. 25, he 

 reports, " The vertebrse comprise a cei*vical, three dorsal, and 

 four caudal vertebras " \. 



The characters of the first two kinds are quoted above. 



" The caudal vertebras are amphicoelian, but not deeply so ; 

 they are subquadrate in section." " The most anterior one 

 of the series has short robust diapophyses, and is more con- 

 cave anteriorly than posteriorly. The other caudals are more 

 equally biconcave ; but the cavity is very shallow on the most 

 distal of them. The centrum is also relatively more elongate 

 and compressed than those of the others. None of them dis- 

 play the lateral pneumatic fossa which exists in the dorsals ; 

 and where broken, so as to permit a view of the internal 

 structure, the latter appears to consist of rather finely spongy 

 tissue. The chevron-facets are not very well defined ; and 

 the neural spines are of the usual forms, and on the anterior 

 two vertebrae elongate. 



" The dorsal vertebra which I suppose to be the anterior 



* Pal. BiUl. no. 25, 1877, p. 5. t IbW- X Ibid. 



