DENTITION. 47 



DENTITION. The dentition of Walruses, for various reasons, 

 lias been a perplexing subject, and lias engaged the attention 

 of many eminent writers. In the adult stage it presents many 

 abnormalities, and, besides, is subject to much individual varia- 

 tion, both in the temporary and adult series. For a long time 

 its deviations from the normal type were not well understood, 

 and even now leading authorities do not appear to be quite in 

 harmony in respect to the proper notation. As previously 

 stated, the incisors of both jaws, except the outer pair in the 

 upper, disappear soon after birth, and before middle life is 

 reached the last tooth of the molar series on each side in both 

 jaws also usually disappears. A brief history of the principal 

 investigations, and opinions held at different times respecting 

 the dentition of the Atlantic Walrus (for the investigations 

 respecting the dentition of this group appear to have been based 

 almost wholly upon this species), is herewith appended as forrn- 

 ing a highly interesting chapter in the technical history of the 

 species. In this historical sketch will be found noted many 

 facts relating to the general subject, given by the authors whose 

 papers are here briefly summarized. 



The dentition of the Atlantic Walrus has been discussed in 

 greater or less detail by Eapp, von Baer, Wiegmann, Fremery, 

 Stannius, Jaeger, Owen, Mahngren, Peters, and various other 

 writers. Wiegmann, in 1838, pretty fully presented the early 

 history of the subject, noting the almost total lack of informa- 

 tion respecting the matter shown by Linne, who evidently paid 

 little attention to the references to the subject made by previ- 

 ous writers. The credit of first giving any definite statement 

 respecting the number of the teeth and their character is due 

 to Anderson, who, in 1734, gave the number of molars as four 

 above and three below. Brisson, in 1756, gave the number as 

 four both above and below ; while Crantz, in 17G5, again gives 

 four above and three below, and quite fairly describes the nor- 

 mal dentition of the adult.* In the same year, Daubenton gave 

 also again four below on each side as well as four above. 



* I append hi full Crautz's description : 



"It had no sharp ineisores in its mouth, and none at all before, but only 

 four teeth on each side ; on the right side of the uuder-jaAv three pretty broad 



concave grinders The two long tusks or horns growing out of 



its face above the nose, and bending down over its month, so as almost to 



barricade it np, seem to be more an impediment than a help to it 



The right tusk is about an inch longer than the left, and its whole length 



