CENTENUS. 



765 



lobes; to those follow two canines in each jaw, and 

 1 these six cheek teeth on each side, the fore- 

 most, one small, and having the character of a false 

 molar ; the others larger, and with sharp tubercles 

 on their crowns, forming true insectivorous teeth. 

 The head is long, the muzzle pointed, the body long, 

 but low on the legs and without any tail ; the ears so 

 short us to be hardly visible; and a slight membrane 

 partially covering the nostrils. In their walking 

 they are plantigrade, and consequently but slow in 

 their motions. They have five toes on each of their 

 feet, armed with sharp claws adapted for digging. 

 They are nocturnal animals, feeding principally upon 

 insects ; and, what is rather singular in animals of so 

 warm a climate, they are described as remaining dor- 

 mant for three months of the year, and this too in the 

 season of greatest heat. 



This last circumstance shows the inaccuracy of any 

 attempt to connect the activity of animals with a 

 higher, and their dormancy with a lower temperature, 

 at least by the general law of animated nature. The 

 truth is, that each animal is adapted to a particular 

 temperature, which ranges over a greater or smaller 

 number of degrees of the thermometer according to 

 circumstances, but which may, in the case of every 

 animal, be exceeded either upward or downwards; 

 and mankind find, by actual experience, that when 

 heat is beyond a certain degree, they become languid 

 and sleepy, in the same manner as when exposed to 

 severe cold. 



We may naturally suppose, on this general prin- 

 ciple, that several of the smaller mammalia of tropical 

 countries hybernate during the hot season, which, if 

 unproductiveness be winter, is the true winter in such 

 countries ; the time when vegetation is burnt up, and 

 many of the insect races either buried deeply in the 

 ground, or in the egg, as preparatory for u new race 

 against the return of the season of plenty. This adap- 

 tation of animal life to the temperature both ways, 

 is a very beautiful instance of that adaptation and 

 balance of all the parts, of which we have so many in 

 every department of nature, animate and inanimate; 

 and it very forcibly illustrates that unity of design 

 which may be traced through the whole. In order 

 that all the different regions of the globe may enjoy 

 as equal a portion of the genial influence of the sun, 

 as can possibly be enjoyed by the surface of a sphe- 

 rical body exposed to a single light, which can of 

 course act upon only the half of it at any one instant,- 

 it became necessary for this purpose to throw the 

 temperature into those diiferent kinds of extremes of 

 season, which we meet with in the tropical and the 

 polar latitudes ; and the effecting- of this general dis- 

 tribution of one cause, necessarily makes an excess of 

 heat the means of suspending and destroying life in 

 the one extreme, just in the same manner as a defi- 

 ciency produces the same result in another. 



There is in this again a very remarkable instance 

 of adaptation, for we find living and growing creatures 

 always in proportion, not to the average temperature 

 of the year, but to that of the particular season. In 

 fact, the cause of the season, and of the abundance or 

 the deficiency which that season displays, is one and 

 the same, so that in proportion to the activity of na- 

 ture generally, is the activity of life and growth of all 

 kinds. Upon this principle, the flowers and steins 

 fail, the insects perish, and the face of nature puts on 

 the same appearance of desolation during the dry and 

 burning months of the warm latitudes, as during the 



frost and snow of the cold ; and though in the former 

 the banks of rivers, and all other places which are 

 supplied with moisture, continue fertile throughout 

 the dry season, there is a corresponding local preser- 

 vation of life in certain parts of the latter : the polar 

 sea is never barren, even when the surface of it is 

 mantled with ice and snow; and it is probable that 

 the drought invades the waters, and thereby produces 

 temporary sterility, to as great an extent in the tro- 

 pical latitudes, as the frost and winter does in the 

 polar ones. Birds, from the power of flight, can escape 

 from the evil day in both localities by migrating ; 

 and fishes have rather more advantage in the cold 

 climate than in the hot ones; because in the first 

 they can move equatorially, so as to avoid the ice, 

 while in the second they are apt to be left stranded, 

 and perish of drought, or become the prey of those 

 wading birds, which frequent the subsiding waters in 

 such multitudes. Some of the fishes are indeed en- 

 dowed with a limited power of making their way 

 upon the dry land, in quest of new pools and streams ; 

 and there is little doubt that some of them hybernate 

 in the warm countries as well as in the cold, just as 

 is the case with mammalia. It is well known that 

 eels, which do not bear the cold so well as many 

 other fishes, hybernate in this country ; and that for 

 this purpose they seek the sludge and mud in the 

 estuaries of the rivers, near the average point of the 

 brackish water, at which the temperature is known to 

 be always higher than either in the fresh of the river, 

 or the open sea. 



We have thought necessary to offer these few 

 remarks on tropical hybernation, both as contrasted 

 with polar, and we may add mountain hybernation, 

 and as it appears to be a necessary part of the system 

 of nature, partly because the hybernation of the ten- 

 rccs have often been described as a sort of anomaly 

 or inconsistency in nature, and partly also for the 

 purpose of showing the beauty and consistency of the 

 system ; and before we proceed to give the few de- 

 tails which are known of the tenrecs, we may further 

 remark, that whenever birds come seasonably, wo 

 may rest assured that, if the country is in a state ot 

 nature, we shall meet with hybernating animals, espe- 

 cially if the birds resort to the place during what may 

 be regarded as its summer. We might naturally 

 conclude that nocturnal insectivorous animals, which 

 are generally plantigrade and have but limited powers 

 of locomotion, would both, from the failure of their 

 food, and the influence of temperature, be among the 

 first to hybernate, whether in the cold latitudes or 

 the warm. We find that such is the case in cold 

 countries and on lofty mountains ; and the tenrecs 

 are one instance of the same in a tropical climate, to 

 which there is little doubt that further observation 

 will add many more. 



There are three species of this genus, differing from 

 each other in size, in colour, and in the texture of 

 their covering ; but their habits, as far as known, are 

 all much the same. 



1. THE BRISTLY. TENREC (Ccntcnus sctaceus]. This 

 is the tenrec of Buffon. It is longer in the body 

 than the common hedgehog, and altogether a little 

 larger, but it is more slender. The front, the top of 

 the neck, and the shoulders, are beset with stiff 

 bristles, annulated with black and pale yellow ; and 

 there are true ones which form a sort of crest on the 

 nape ; the back, the flanks, and the rump, are covered 

 with stouter bristles ; but even these are partly flexU 



