ELEPHANT AND MASTODON. 25 



round to the opinion advanced by other observers, that it was a 

 true Pachydermatous form, 1 closely allied to Mastodon. 



The discussion respecting Tetracaidodon, which had been sus- 

 pended in America, was renewed in England on the occasion of 

 Koch's public exhibition of the entire skeleton, and other remains 

 of the North American Mastodon, in London, during 1841. The 

 ingenious exhibitor contrived a fanciful reconstruction of the ske- 

 leton inconsistent with the principles of animal mechanics. The 

 huge tusks, instead of being placed with their points directed 

 upwards, as in the Elephant, or downwards, as had been formerly 

 suggested by Mr. Rembrandt Peale, 2 were spread out horizontally 

 with diverging curves, so as to resemble two great sickles. Other 

 corresponding extravagancies were exhibited in the apposition of 

 the limbs, and for the grotesque form so constructed, Mr. Koch 

 proposed a distinct generic place, under the designation of Mis- 

 sourium.^ Professor Owen, on this occasion, reviewed the whole 

 of the evidence respecting Tetracaidodon, and, in a masterly com- 

 munication to the Geological Society, extended the objections 

 urged by the American naturalists, by numerous and forcible 

 analogies drawn from the dentition of the Dugong and Narwahl, 

 besides some of the ordinary Pachydermata. 4 He arrived at the 

 conclusion, that the Mastodontoid animals of North America are 

 all strictly referable to a single species, which " has two lower 

 tusks originally in both sexes, and retains the right lower tusk only 

 in the adult male." Dr. Grant entered upon an elaborate investi- 

 gation of the same subject soon afterwards, and was led to very 

 different results. 5 He divides the Proboscidean Pachydermata 



1 Akten der Urwelt, 1841. 2 Cuv. Oss. Foss. torn. i. p. 239. 



3 Koch has lately published a separate memoir, in which the Missourium is 

 figured and perpetuated with all its original exaggeration. He has given it the 

 appropriate specific name of M. theristocaulodon, the tusks being invested with the 

 functions of a sort of scythe. — A. C. Koch, 'Die Riesenthiere der Urwelt oder das neu 

 entdeckte Missourium theristocaulodon, und die Mastodonten im Allgemeinen und 

 Besondern.' Berlin, 1845. 



* Owen, « Proceedings of the Geol. Soc' Feb. 1842, vol. iii. p. 659 j ' Report on the 

 Missourium.' 



5 Grant, loc. cit. June 1842, p. 770, ' On the Structure and History of the Masto- 

 dontoid Animals of North America.' 



