BECKKAilVi; NATURAL HISTOBY. 



upon which tho head and foet are again thrust out, and the 

 has time to dine. Creatnrea furnished with 

 Hiirh :i defence liave no need for rapid flight, an d therefore the 

 unnecessary power is withhold. 



of our reader* are probably aware that the upper shell 

 tortoise is called the carapace and tho under tho plastron. 

 i singular structures demand a few notices. Tho ribs of 



ire really outside the body, tho carapace being com- 

 posed of eight pairs of flat ribs, which thus form an expanded 

 bony covering. The spaces botwoon tho ribs aro filled up by 

 tough shelly platen, forming so rigid a shield that some 

 naturalist declared the wheel of a heavily-laden wagon might 

 pass over the wholo without breaking any of tho plates. Tho 

 will now see why tho ribs are placed outsido the body. 

 Tim problem was, to form an invulnerable covering with tho 

 i uoonvenionoo to the animal. Had the ribs remained 

 within tho body, and a heavy case been placed on the outsido, 

 tho tortoise would have boon terribly over-weighted. This has 

 been avoided by making tho ribs themselves serve for tho pro- 

 tecting-shiold, while they still perform their usual work in the 

 animal's system. Tho plastron, or breastplate, is formed on 

 the same general plan, consisting of nine bony plates, eight 

 being arranged in pairs. Tho unprotected spaces, seen be- 

 tween the various parts of the shield in young and fresh-water 

 tortoises, are gradually filled with bone as the animals grow. 

 The "sutures," which join tho ribs of the carapace, resemble 

 very much, especially in young turtles, the lines of union 

 between the eight bones of an infant's head. In a few turtles, 

 and in the species called " soft tortoises," some parts of tho 

 shield consist only of plates of cartilage, which connect tho bony 

 portions together. 



The tortoise is far too peaceable to bo a military teacher, but 

 the readers of Roman history will not fail to remember tho 

 famous formation of a column of infantry called " a tortoise," 

 a name evidently suggested by the buckler of tho animal. 

 When a column of men advanced to tho walls of a hostile town, 

 the troops sheltered themselves from the showers of stones and 

 darts by firmly interlacing their shields. An iron roof was thus 

 raised over the heads of the assaulting column. Tho manoeuvre 

 was not inaptly described as " the making of a tortoise." 



The carapace and plastron are not tho only peculiarities of 

 structure which call for notice. Tho position of the shoulder- 

 blade (scapula) is truly remarkable. The reader who will place 

 his hand behind either of his shoulders will feel that the bone 

 rests upon tho ribs, but as these aro outside the body of the 

 tortoise it follows that the shoulder-blade must be inside tho 

 ribs. Thus an anatomist might describe tho animal as " turned 

 inside out," if he rogard the position of tho ribs ; or " outside 

 in," if he consider only the singular place of the shoulder-blade. 

 These peculiarities of structure strongly influence tho motions 

 of the tortoise, but do not deviate from the unity of plan seen 

 in vertebratod animals. Tho ribs and shonlder-blade are not 

 absent, but wonderfully modified to suit the peculiar wants of 

 the animal. 



The stomach of the turtle seems as if specially fitted to con- 

 vert coarse masses of sea-weed into that delicious fat so prized 

 by the epicure. Vast, indeed, seems the distance between the 

 reptile feeding on a mass of tangled weed at the bottom of the 

 sea and the brilliant illumination of a great civic banquet hall. 

 There the tureens of turtle-soup contain the results of tho 

 strange animal chemistry which has changed sea-weeds into 

 that which delights every guest. The muscular coat of tho 

 stomach in the turtle is so admirably adapted to digest the 

 coarsest vegetable fibre, that the Royal College of Surgeons 

 have not deemed it beneath the dignity of science to preserve 

 specimens of such a digestive apparatus in their museum. In 

 truth, the bill, tongue, gullet, and stomach are all adapted for 

 a digestive work of the highest order. 



We should have supposed that reptiles which sometimes weigh 

 above 1,500 pounds must not only have good digestion but also 

 a most perfect circulating system, to convey the rich blood to 

 every part. So far from this being the cose, it is ascertained 

 that some of tho blood which has goue round the body, and is 

 therefore vitiated, does not pass through the lungs to undergo 

 the purifying process. It is actually sent round again in its 

 deteriorated state, and the turtles do not die of consumption, 

 but produce the richest food for human epicures. This is 

 another puzzling peculiarity in the structure of these creatures. 



The brain and nervous system of the tortoue hre received 

 much attention from physiologists ; the reason tor this will 

 soon bo understood. When such men as the famous John 

 Hunter, Cuviur, Professor Owen, and other great anatomist*, 

 make the brain and nerres of a tortoise their special study, we 

 may be sure some deep problem awaits solution. Perhaps we 

 shall best suggest the object sought in all these investigations 

 by stating in a few words the experiments of the Italian natu- 

 ralist, liedi. We have nothing here to do with the question 

 whether such anatomical studies on living animals can be justi- 

 fied. Our space will not allow of the discussion of such a topic, 

 and wo must, therefore, simply take the facts as they are pre- 

 sented. The first experiment was performed on a common 

 tortoise, tho skull of which Bedi opened, and removed the whole 

 of the brain. Not satisfied with the mere extraction of the 

 general moss, he actually scraped and washed out the cavity, so 

 that no particle of nervous matter might remain. The Earl of 

 Stratford would have called this part of the process "thorough." 

 Some readers may suppose that the immediate death of the 

 tortoise was tho result. No such thing ; the creature simply 

 closed its eyes, and then gently moved about as if nothing very 

 important had happened. Muscular power clearly remained, 

 nor were there any signs of suffering. The vital energies were 

 unaffected, for so rapidly did the healing process go on that the 

 wound in tho skull was co/ered with new skin in the short space 

 of three days. The operation was performed in November, 

 and the animal lived and moved about until the 15th of May. 

 When this tortoise was examined after death, no signs of the 

 formation of any new brain appeared. The experiment was re- 

 peated upon other tortoises, both land and fresh-water, and also 

 on a turtle. The results were by no means uniform. Some of 

 tho brainless reptiles were able to move about with ease, others 

 lost the power of locomotion ; some lived for a considerable time 

 after tho operation, others died in about a week. Bedi next 

 went a step further by cutting off tho head of a tortoise alto- 

 gether, and noting the results. The animal managed to live 

 without its head for twenty-three days, and retained the power 

 of moving the limbs, but not of walking about. Two tortoises 

 which had lost their heads in a similar manner, preserved so 

 much vital energy that their hearts continued to beat and the 

 blood to circulate for twelve days after decapitation ! All these 

 facts demonstrate that life is not destroyed in the tortoise by 

 the mere loss of brain or head. We admit that these and other 

 experiments have not brought us to a clearer insight into the 

 mystery called life: the problem is still unsolved. We see 

 plainly enough, however, that in these reptiles life is not alto- 

 gether dependent on the brain, as vital action continues long 

 after the brain has gone. 



The eye of tho tortoise might be described at great length, 

 but want of space compels us to be very brief on this topic. 

 The possession of three eyelids is common in birds, but we 

 should not have expected to find such a defensive organisation 

 in these slow-moving reptiles. Each eye has also two tear- 

 glands, the object of the small one called the Harderian gland 

 being to provide the third eyelid with the fluid necessary to 

 give facility to its horizontal motion across the eye. 



The tortoise family cannot rank very high among the animals 

 useful to man. They supply food to a few tropical tribes, who 

 use the huge carapaces of the larger species for vessels, and 

 even for canoes. Some may remind us of the beautiful tortoise- 

 shell furnished by one species of turtle ; but pretty or even 

 elegant combs and ornaments do not, after all, materially in- 

 fluence the happiness of man. These reptiles appear to possess 

 a fair share of animal intelligence. Even the slow common 

 tortoise learns to recognise those who pet it ; but it is chiefly 

 among the large tropical species that "cleverness" is found. 

 Many of the volcanic islands near the equator swarm with giant 

 tortoises, which are said to find out the remote mountain 

 springs when tho ingenuity of tho natives is entirely at fault. 

 We must admit, too, that the turtles show what may be called 

 "judgment" in selecting and forming the nests for their eggs. 

 These are not mere holes in the sand ; the reptile constructs 

 covering over her eggs thin enough to allow the heat of the sun 

 to enter, and yet sufficiently solid to protect the contents of the 

 nest from the chilling damps of night. The mere position of the 

 nests is a matter of importance, for if not placed above high- 

 water mark, tho first tide would sweep away the eggs. Let no 

 reader smile incredulously if we venture to allow some degree 



