EDEN 



ences and anomalies in a comparatively limited 

 number of genera and families, that they perhaps 

 throw more difficulties in the way of a clear under- 

 standing of the system of nature, than any other of 

 the vertebrated animals. 



They are divided by Cnvier into three tribes ; 

 Tardigrada, or "slow walkers ;" Edentata, or tooth- 

 less animals, properly so called ; \<\ Mimotrematrt, or 

 those which have but one cloaca, or vent, as in birds. 



The first i'amily consists of but one single living 

 group, the sloths, of which some account will be 

 found in the article Ai ; they have only the fore teeth 

 wanting ; for they are provided with cylindrical 

 molars and with pointed canine teeth of greater 

 length ; they are furnished with numerous claws to 

 the toes, by means of which they suspend themselves 

 to the branches of trees, and walk or repose with the 

 back downwards. 



Connected with this single existing genus, though 

 Jittering from it by being much larger in size, and 

 also in some other important particulars, there are 

 two extinct genera, both natives of the same parts of 

 the world in which the existing genus is found, that is 

 in South America. These are the Megatherium, which 

 from the skeleton must have been an animal of large 

 size, and the -Megnlonyx, which, though larger than 

 any of the existing species, must have been less than 

 the former. 



These are both fossil animals, and, of course, 

 only their skeletons are known to us ; but these have 

 been found in a state of sufficient perfection for 

 enabling, at lea^t, some judgment to be formed of 

 what the animate must, I'u^e been when alive. They 

 appear to have held a sort of middle station between 

 the sloths and the ant-caters, Dreeing with the 

 former in many parts of the skeleton, but being 

 without the produced and pointed canine teeth. Of 

 the state of the country where such formidable 

 animals of this kind were necessarv (and if they had 

 not been necessary as p^rt of the general system they 

 would not have existed), we cannot possibly form 

 any idea, but they carry us buck to a state of things 

 very different from the present ; and from the 

 description of countries which we find the sloths and 

 the ant-eaters now inhabiting, we can at least form 

 some rude guess at that which was more general 

 when the larger animals of similar structure were 

 required for the proper working of the system. The 

 sloths are found only in those parts of South America 

 where the ground is covered with thick forests, and 

 subject to seasonal inundations ; and the ant-eaters 

 are found only in places where there is an exuberance 

 of ligneous vegetation, of the substance of which 

 small insects of various kinds, but all in general 

 known by the name of ants, are the natural de- 

 stroyers. We are, therefore, to infer that, in the 

 early times, when more powerful animals of similar 

 .structure, and therefore, as we may suppose, of 

 similar habits, were necessary, there must have been 

 upon the earth a more general and rapid production 

 of ligneous vegetation, which required a still greater 

 abundance of the wood-destroying insects than we 

 find in the tropical forests at the present time, and 

 the greater abundance of this must have rendered a 

 greater number of those animals which prey upon 

 them necessary for the proper working of the system 

 and the due preservation of all the races. 



From the form of our globe, the place which it 

 holds in the system, the motions which it performs, 

 NAT. HIST. Vol.. II. 



TATA. sss 



and the consequent mode of the distribution upon it 

 of that influence of the sun which is the grand 

 stimulus of all kinds of life, every species of produc- 

 tion and action upon it, wherever it may have taken 

 place, must have been seasonal must "have had its 

 spring, its maturity, its fall, and its repose. 



Without any reference to the Great First Cause 

 by which the universe is regulated, our earth is 

 under the controul of fur more powerful energies 

 than any of a merely terrestrial character or origin. 

 Jt is part of the same system, the laws of which are 

 not one jot. affected by anything that can take place 

 on the surface of the earth. The mere quantity, that 

 is, the weight of matter in it, is the only property of 

 it which comes within the general laws of the system ; 

 and however the volume, the combinations, or the 

 other apparent qualities of the matter of the earth, 

 may change, the quantity, as measured by the gravi- 

 tation, must remain the same, unless ahered by the 

 direct interposition of the same Being that called it 

 into existence. The orbital motion of the earth must 

 re, rain constant, with the exception of those small 

 variations in loni}- periods of time which the influence 

 of the other bodies of the system impose upon it, and 

 the extent and limits of which are matters of certain 

 and not very difficult calculation. Those variations 

 are so small, and the periods over which ihey extend 

 are so long, that they can have no effect whatever 

 upon any part of the economy of the earth's surface 

 during the life of man, or the wh<le time of man's 

 history. Therefore, we may leave them out of view, 

 and consider the grand seasonal action of the sun 

 upon the earth as being at all times one and the 

 same, as told in the different hours of the day, and 

 the successive days of the orbital revolution. 



We have this as an unquestionably sure foundation 

 in all those speculations and inquiries into nature 

 which are of a more general kind than the simple 

 examination of that which comes before our eyes as 

 mortals. Those speculations are by far the most 

 valuable portions of the subject, for they lead the 

 mind to immortality, and give it immortal hope, 

 which is of far more importance than anything which 

 is confined to our few years of trouble and vexation 

 in this world. 



In consequence of this general law of the system, 

 which is far more immutable upon the earth than the 

 laws of the Medcs and Persians were upon the 

 subjects of those departed and all-bul-tbrgotten 

 states, we may be sure that the general action of the 

 seasons, as dependent on the sun, must have been the 

 same in all ages, how differently soever the surface of 

 the earth over the whole, or in any region, may have 

 obeyed or been affected by that action. The exist- 

 ence of these last animals which have led us to these 

 few remarks and v*e regret that our limits will not 

 admit of our following them out, and we do this the 

 more that we believe the subject is but seldom 

 brought before the public generally, even to such an 

 extent as to call attention to it the existence of 

 these animals speaks of a time of forests and flood- 

 ings ; and we know that in all places of the world 

 where these aiv, there are alternating periods of 

 drought. During the flood we may suppose that the 

 whole of the timber-destroying insects were swept 

 away ; but that, as the eggs of all are proof against 

 every change of nature, and many of them are actually 

 committed to the waters, there was always a store for 

 the production of fresh myriads as soon as the 

 8 B 



