546 



II E P T I L E. 



size, the strength, and the venom whatever tin- 

 creature lias to depend upon for its strength and 

 protection is always in proportion to the general 

 action of nature in the place which it inlmbits. 



Those which have their habitations in the sea, 

 also, all point to the tropical countries as their head- 

 quarters ; and they, as well as the land ones, so far 

 follow the climatal distinction of the two hemispheres, 

 as that they go into higher latitudes in the southern 

 hemisphere than in the northern. As we get into 

 the high latitudes, the numbers, the size, and the 

 power of reptiles, whether of the land, the fresh 

 waters, or the sea, rapidly decrease, till, in the extreme 

 regions near the poles, there are few or none. The 

 northern hemisphere has been examined with the 

 greatest care ; and it affords the best field for 

 examination, as there is, in one longitude or another, 

 continuous land all the way from the equator to the 

 polar ice. 



From the examination of it, we find, that the sea- 

 reptiles are the first to fail, while the fresh-water ones 

 are among the last. We might be prepared to 

 expect this, from the fact, that very few animals can 

 hybernate in the sea, and none, perhaps, in the deep 

 water. It has been alleged, that some of the surface 

 fishes, as, for instance, the mackerel, sink down into 

 the deep water, and remain dormant there at certain 

 seasons of the year ; but the point would be very 

 difficult to establish, and we are not aware of the 

 existence of any sea reptile which hybernates. Even 

 in the warmer seas of Europe, reptiles are few ; and 

 in the British seas there do not appear to be any 

 residents, and very few stragglers. In the fresh 

 waters there are none but batrachians ; and the land 

 ones are not many, and in the northern parts they 

 are exceedingly rare. 



On the continent it is different ; for fresh water 

 tortoises are found nearly up to the southern shores 

 of the Baltic, and there are poisonous serpents in 

 Sweden and Norway. This also is what we might 

 be prepared to expect ; for, as these are hybernating 

 animals, they do not depend on the average tempe- 

 rature of the year, but on the heat of the summer, or 

 season of their activity ; and, though the. average 

 temperature is lower in the countries mentioned than 

 it is in Britain, yet the excess of cold is thrown upon 

 the winter, and the summer is considerably warmer. 

 We have a very good illustration of this in many 

 parts of Scotland, where there are snakes in the 

 hills, while not one is ever seen upon the plains 

 between these hills and the sea, though the average 

 of the year is much milder there. The summer, 

 however, is not nearly so warm, at least during the 

 day, as these plains are cooled by the sea breezes, 

 while the heat among the hills is increased by 

 reflection, till, in some places, it is as high as summer 

 tropical ones, and it lasts for a longer portion of the 

 day, from the sun being, for several weeks in the 

 middle of the summer, four or five hours longer 

 above the horizon. 



From the way in which they are distributed, we 

 can thus see how the present race of reptiles is 

 affected by the physical character of the climate ; 

 and as that confines by far the greater number of 

 them, and all the most powerful ones, to the warm 

 latitudes, we may naturally conclude that these are 

 the only places where they are now required in the 

 economy of wild nature. 



In former times it must have been very different, 

 for we have very numerous remains of fossil reptiles 



in the northern parts of the world, and in England 

 ia particular ; which proves that, at some former 

 period, they must have been a conspicuous, and 

 therefore an essential part, in the system of animal 

 economy. The fossil reptiles which have been found 

 in various formations, more or less consolidated into 

 stone, are chiefly, if not wholly, either cheloniau or 

 saurian. The t'/iefania are of the forms now inha- 

 biting the waters, some of them apparently of the 

 fresh waters, but the greater part of the sea. Remains 

 of crocodiles are not rare, some of them bearing a 

 resemblance to the existing species, and some not ; 

 but of many of the other fossil sauria there are no 

 existing types, neither are there any living members 

 of the order which rival some of them in size. 



But, though the reptiles which have the nearest 

 resemblance to these extinct species are now found 

 only in more tropical climates, that proves nothing 

 wkh regard to the climate of England in former 

 times, nor, which would be more to our present 

 purpose, does it throw any light upon the nature of 

 reptiles. We know, from the almost perfect remains 

 found in the north of Siberia, that there must at one 

 time have been elephants not an occasional strag- 

 gler, but in such numbers that the teeth formed a con- 

 siderable article of trade so formed as to endure the 

 very extreme of cold, and with bristly hairs inter- 

 spersed with their fur, capable of shaking off a fall of 

 snow, however heavy. The remains of the other 

 Pachydcrmata which are met with indicate a marshy 

 state of the 'country ; and, as these great fossil rep- 

 tiles, which, from their situations in the earth, are 

 obviously of much more early date than the extinct 

 mammalia, are all aquatic, we may conclude that the 

 northern parts of the world have been in a progress 

 towards dryness, which, from what we at present 

 observe, is one means of unfitting them for the abodes 

 of reptiles. 



This gives us another physiological character of 

 the class, which, though of rather a shadowy nature, 

 is yet of some use in a case where we can found so 

 little upon organisation, and also lets us see the 

 reason of the difficulty we labour under in endeavour- 

 ing to get a general understanding of the nature of 

 this perplexing class of animals. The reptiles are not 

 peculiarly land animals (including both mammalia 

 and birds under that denomination), neither are they 

 aquatic animals ; but they are animals of the bound- 

 ary between the two, and thus have no breadth of 

 native locality in which we can link them with vege- 

 tation, or otherwise bring them within the general 

 laws of the rest of the system as we now observe it. 

 With only one or two exceptions, they all, when in 

 the native state, breathe the free air like land 

 animals, but they do it slowly and imperfectly ; and 

 many of them even suspend their animation for a 

 great length of time, or rather, it becomes suspended 

 of its own accord, when the stimulus of heat is suffi- 

 ciently lowered. 



In the production of their young, they vary from a 

 resemblance to the birds to a resemblance to the 

 fishes ; and in the last part of the series they resemble 

 both kinds of fishes, in some being oviparous and 

 others ovoviviparous. The very texture of their 

 bodies, bones, membranes,-fibres, and all, have some- 

 thing of this intermediate character. The bones 

 contain less phosphate of lime than those of the mam- 

 malia and birds, but more than those of the fishes, 

 and gelatine predominates in all the soft tissues and 

 structures of their bodies. 



