TRANSACTIONS OF SECTION D.— DEPT. ZOOLOGY AND BOTANT. 553 



.an animal's position upon such a trivial character when opposed to the totality of 

 its organization and habits. 



The characters of the incisor teeth are placed in the first rank in the definitions 

 of all the orders in the Systema Natures, and hence the next order called Bruta, 

 characterized by 'dentes primores nulli superius aut inferim,' contains a curious 

 mixture of heterogeneous animals, as the names of the genera Elephas, Trichechus, 

 Bradypus, Myrmecophaga, Manis, and Dasypus will indicate. It contains, in fact, 

 all the animals then known comprised in the modern orders of Proboscidea, 

 Sirenia, and Edentata, together with the walrus, one of the Camivora. The name 

 Bruta has been revived for one of these orders, that more generally called Edentata, 

 but I think very inappropriately, for it was certainly not equivalent, and if re- 

 tained at all, should rather belong to the Pi-oboscidea, as Elephas stands first in 

 the list of genera, and was probably in the mind of Linnaeus when he assigned 

 the name to the group. 



It is curious to find that the striking differences between the African and the 

 Indian elephants, now so well understood by every beginner in Zoology, and all 

 the facts which have already been accumulated relating to the numerous extinct 

 forms of Proboscideans, whether Mammoths, Mastodons, or Dinotheria, were quite 

 unknown to Linnaeus. .One species only, Elephas ma.vimus, represented in the 

 zoology of a hundred years ago, was all that was known of the elephants or 

 elephant-like animals. 



The genus Trichechus of this edition exhibits a very curious phase of zoological 

 knowledge : It contains two species. 1. T. rosmarus, the Walrus, now known to 

 be a modified seal, and therefore a member of the Linnaean order Fer^, and 2. T. 

 manatus, a name under which were included all the known forms of Manatees and 

 Dugongs, in fact the whole of the modern order Sirenia ; animals widely removed 

 in all essential points of their organization from the walrus, with which they are 

 here generically united. Their position, however, between the elephant on the one 

 hand and the sloths on the other, is far better than their association with the 

 Cetacea, as in Cuvier's system, an association from which it has been most difficult 

 to disengage them, notwithstanding their total dissimilarity, except in a few ex- 

 ternal characters. Although the discovery of many fossil forms has done much 

 to link together the few existing species and to show the essential unity of the 

 group, it has thrown no light upon their origin, or their affinities to other mam- 

 mals. They still stand, both by their structure and their habits, a strangely 

 isolated group, and it baffles conjecture to say whence they have been derived, or 

 how they have attained their present singular organization. 



The remaining genera of the Linnaean order Brtjta constitute the group out of 

 •which Ouvier, following Blumenbach, formed his order Edentata, a name certainly 

 not happily chosen for a division which includes species like the great Armadillo, 

 having a larger number of teeth than any other land mammal, but which, neverthe- 

 less, has been so generally adopted, and is so well understood, that to attempt to 

 change it would only introduce an element of confusion. Four out of five of the 

 principal modifications of form in the group at present known, are indicated by the 

 four Linnaean genera, Bradypus or Sloth, Myrmecophaga or Anteater, Manis or 

 Pangolin, and Dasypus or Armadillo. The advances during the century have con- 

 sisted in the accumulation of a great mass of details respecting these groups ; the 

 addition of a fifth and very distinct existing form, the Orycteropus or Cape Ant- 

 eater ; and the discovery of numerous and very remarkable extinct forms, such as 

 the Megatheriums and Glyptodons of South America, so fully known by their 

 well-preserved osseous remains. There is, however, still much to be done in work- 

 ing out the real relationship of the somewhat isolated members of the order, if it 

 be a natural order, both to each other, and to the rest of the Mammalia, from which 

 they stand widely removed in many points of organization. 



The third order of Linnaeus, Fer^:, contained all the then known animals, 

 which, with whatever diversities of general structure, agreed in their predatory 

 habits, and possessed certain general characters of teeth and claws to correspond, 

 though the terse definition of " Dentes jn-imores superiores sex, acutiusadi, canini 

 talitarii" is by no means universally applicable to them. This order was broken 



