18 THE GENUS ODOB^NUS. 



with tliose of the Gnlph of St. Laurence. The tusks of those 

 of the Frozen Sea are much longer, more slender, and have a 

 twist and inward curvature."* Shaw, a few years later, thought 

 that the Walrus described and figured in the account of Cap- 

 taiu Cook's last voyage, though perhaps not specifically distinct 

 from those of the Arctic shores of Europe, should be regarded 

 as belonging to a different variety.t He appears, however, to 

 have based his opinion wholly on figures of the animals, and par- 

 ticularly on those given by Cook and Jonston (the latter a copy 

 of Gerrard's, at second-hand from De Laet). Ilhger, in 1811, 

 formally recognized two sx)ecies in his " Ueberblick der Saug- 

 thiere nach ihrer Yertheilung iiber die Welttheile,"| namely, 

 TricJiechus rosmarus, occurring on the northern shores of (West- 

 ern?) Asia, Europe, and North America, and T. ohesus, occur- 

 ring on the northwestern shores of I^forth America and the ad- 

 joining northeastern shores of Asia. While I do not find that 

 he has anywhere given the distinctive characters of those two 

 species, he, in the above-cited i)aper, also named the animal 

 described and figured by Cook, T. divergens. F. Cuvier, in 1825, 

 in describiug the dentition of the "Morses," says : " Ces dents ont 

 ete decrites d'apres plusieurs tetes qui semblent avoir appartenu 

 a deux especes, a en juger du moins par les proportions de quel- 

 ques unes de leurs parties, et non seulement par I'^tendue de 

 leurs defenses, caractere qui avait d6ja fait soui^gonner a Shaw 



* Arctic Zoology, vol. i, 1792, pp. 170, 171. 



tHe says: "An excellent representation is also given in pi. 52 of the 

 last voyage of our illustrious navigator, Captain Cook. It is easy to see, 

 liowever, a remarkable diiference between the tusks of tMs last, and tliose 

 of the former kind figured in Jonston, and it clearly appears, that though 

 this difference is not such as to justify our considering them as two distinct 

 species, yet it obliges us to remark them as varieties ; and it should seem, 

 that, in the regions then visited by Captain Cook, viz. the icy coasts of the 

 American continent, in lat. 70, the Walrus is fomid with tusks much longer, 

 thinner, and far more sharp-pointed, in jiroiiortiou, than the common Wal- 

 rus ; and they have a slight inclination to a subspiral twist : there is also 

 a difference in the position of the tusks in the two animals ; those of the 

 variety figured in Captain Cook's voyage curving inwards in such a manner 

 as nearly to meet at the points, while those of the former divarica.te. These 

 differences aj)pear very striking on collating different heads of these ani- 

 mals. Something may, however, be allowed to the different stages of growth 

 as well as to the difference of sex. In order that these differences may be 

 the more clearly understood, we have figured both varieties on the annexed 

 plates ^'General Zoology, vol. i, 1800, pp. 236, 237, pis. 68, 68*. 



t Abhandl. der Akad. der Wissensch. zu Berlin, 1804-1811, p. 64. Read 

 before the Academy Feb. 28, 1811, but apparently not published till 1815. 



