4-40 Loomis — An Unusual Mastodon. 



distinguish these two specimens as a new species, dis- 

 tinguished from the American mastodon by the features 

 above mentioned, but the large number of known speci- 

 mens indicate that there is considerable range of varia- 

 tion in the mastodons, not only on account of age and sex, 

 but also individual. As far as I can find from studying 

 the reports of mastodons over the country, those from 

 the south seem to range larger in general, and more fre- 

 quently to show the more complicated molars. > 



The most striking feature is the presence of the well- 

 developed tusks in the lower jaws which at once revives 

 the Tetracaulodon discussion started by Godman in 1830 2 

 when he gave the name Tetracaulodon to a specimen 

 which he found with a small tusk in the lower jaw. This 

 specimen came from Newburg, N. Y., and had a small 

 tusk four inches in length, together with the alveolus for 

 its mate. Hays 3 confirmed the feature and cited three 

 other specimens, presumably from Big Bone Lick, which 

 either had lower tusks or alveoli for them. He further 

 showed that some young had the tusks and some no trace 

 of them. The tusks referred to by Hays are much 

 larger, one of them being 11 inches long and two inches 

 in diameter. In 1852 Warren 4 in his classic memoir 

 described the skeleton of his big mastodon from New- 

 burg, N. Y., which to date has been the largest recorded 

 mastodon. This had one tusk present in the lower jaw 

 and the alveolus for the other partly filled with bone. 

 He examined sixteen lower jaws, in nine of which tusks 

 or alveoli for them were present. He found that the 

 skeletal portions of those with tusks and those without 

 were similar and concluded that the lower tusk is not a 

 specific, but a sexual character ; the tetracaulodon forms 

 representing the males, those Avithout the tusks the 

 females. Warren's position has since then been generally 

 accepted. Cope in 1889 says 5 "mandibular tusks are 

 present in the young and occasionally retained to matur- 

 ity. ' ' And Matthew" uses the presence or absence of man- 

 dibular tusks to determine the sex, the tusk being the mark 

 of the male. In the St. Helena specimen under discussion 

 there were two lower tusks, each 10% inches long and 2^ 



- Trans. Amer. Phil. Soc, 1830, new series, Vol. 3, p. 478. 



3 Trans. Amer. Phil. Soe., new series, Vol. 4, 1834, p. 317. 



1 The Mastodon giganteus of North America. 



15 American Naturalist, vol. 23, p. 197. 



Mammoths and Mastodons, Amer. Museum Guide Leaflet 43, 1915. 



