flat to catch the sunlight. No other at all analogous to our own. V. SLUGS AND SNAILS. A wasp whose head has been severed from its body and stuck upon a pin, will still greedily suck up honey with its throatless mouth; while an Italian mantis, similarly treated, will calmly continue to hunt and dart at midges with its decapitated trunk and limbs, quite forgetful of the fact that it has got no mandibles left to eat them with. These peculiarities lead one to hope that insects may feel pain less than we fear. Yet I dare scarcely utter the hope, lest it should lead any thoughtless hearer to act upon the very questionable belief, as they say even the amiable enthusiasts of Port Royal acted upon the doctrine that animals were mere unconscious automata, by pushing their theory to the too practical length of active cruelty. Let us at least give the slugs and beetles the benefit of the doubt. People often say that science makes men unfeeling for my own part, I fancy it makes them only the more humane, since they are the better able dimly to figure to themselves the pleasures and pains of humbler beings as they really are. The man of science : HOEING among the flower-beds on my lawn this morning-for I am a bit of a gardener in my way-I have had the ill-luck to maim a poor yellow slug, who had hidden himself among the en-perhaps realizes more vividly than all croaching grass on the edge of my lit- other men the inner life and vague tle parterre of sky-blue lobelias. This rights even of crawling worms and ugly unavoidable wounding and hacking of earwigs. worms and insects, despite all one's I will take up this poor slug whose care, is no small drawback to the pleas- mishap has set me preaching, and put ures of gardening in propriâ persona. him out of his misery at once, if misVivisection for genuine scientific pur- ery it be. My hoe has cut through the poses in responsible hands, one can soft flesh of the mantle and hit against understand and tolerate, even though the little embedded shell. Very few lacking the heart for it one's self; but people know that a slug has a shell, but the useless and causeless vivisection it has, though vivisection it has, though quite hidden from which cannot be prevented in every or- view; at least, in this yellow kinddinary piece of farm-work seems a gra- for there are other sorts which have got tuitous blot upon the face of beneficent nature. My only consolation lies in the half-formed belief that feeling among these lower creatures is indefinite, and that pain appears to affect them far less acutely than it affects warmblooded animals. Their nerves are so rudely distributed in loose knots all over the body, instead of being closely bound together into a single central system as with ourselves, that they can scarcely possess a consciousness of pain rid of it altogether. I am not sure that I have wounded the poor thing very seriously; for the shell protects the heart and vital organs, and the hoe has glanced off on striking it, so that the mantle alone is injured, and that, by no means irrecoverably. Snail flesh heals fast, and on the whole I shall be justified, I think, in letting him go. But it is a very curious thing that this slug should have a shell at all! Of course it is by descent a snail, and, in secrete the shell in their remote ancestors have either ceased to work altogether or are reduced to performing a useless office by mere organic routine. deed, there are very few differences be- tered up and down through the mantween the two races except in the pres-tle; and sometimes even these are ence or absence of a house. You may wanting. The organs which used to trace a curiously complete set of gradations between the perfect snail and the perfect slug in this respect; for all the intermediate forms still survive with only an almost imperceptible gap be- The reason why some mollusks have tween each species and the next. Some thus lost their shells is clear enough. kinds, like the common brown garden Shells are of two kinds, calcareous and snail, have comparatively small bodies horny. Both of them require more or and big shells, so that they can retire less lime or other mineral matters, comfortably within them when at- though in varying proportions. Now, tacked; and if they only had a lid or the snails which thrive best on the bare door to their houses they could shut chalk downs behind my little combe themselves up hermetically, as peri- belong to that pretty banded black-andwinkles and similar mollusks actually white sort which everybody must have do. Other kinds, like the pretty gold-noticed feeding in abundance on all en amber-snails which frequent marshy chalk soils. Indeed, Sussex farmers places, have a body much too big for will tell you that South Down mutton its house, so that they cannot possibly owes its excellence to these fat little retire within their shells completely. mollusks, not to the scanty herbage of Then come a number of intermediate their thin pasture-lands. The pretty species, each with progressively smaller banded shells in question are almost and thinner shells, till at length we wholly composed of lime, which the reach the testacella, which has only a snails can, of course, obtain in any resort of limpet-shaped shield on his tail, quired quantity from the chalk. In so that he is generally recognized as be- most limestone districts you will simiing the first of the slugs rather than larly find that snails with calcareous the last of the snails. You will not shells predominate. But if you go into find a testacella unless you particularly a granite or sandstone tract you will see look for him, for he seldom comes that horny shells have it all their own above ground, being a most bloodthirsty way. Now, some snails with such subterraneous carnivore who follows the houses took to living in very damp and burrows of earthworms as savagely as a marshy places, which they were natuferret tracks those of rabbits; but in rally apt to do-as indeed the landall the southern and western counties snails in a body are merely pond-snails you may light upon stray specimens if which have taken to crawling up the you search carefully in damp places leaves of marsh-plants, and have thus under fallen leaves. Even in testacellæ, gradually acclimatized themselves to a however, the small shell is still external. terrestrial existence. We can trace a In this yellow slug here, on the con- perfectly regular series from the most trary, it does not show itself at all, but aquatic to the most land-loving species, is buried under the closely wrinkled just as I have tried to trace a regular skin of the glossy mantle. It has be-series from the shell-bearing snails to come a mere saucer, with no more the shell-less slugs. Well, when the symmetry or regularity than an oyster- earliest common ancestor of both these shell. Among the various kinds of last-named races first took to living slugs, you may watch this relic or rudi- above water, he possessed a horny shell ment gradually dwindling further and (like that of the amber-snail), which further towards annihilation; till final- his progenitors used to manufacture ly, in the great fat black slugs which from the mineral matters dissolved in appear so plentifully on the roads after their native streams. Some of the summer showers, it is represented only younger branches descended from this by a few rough calcareous grains, scat-primeval land-snail took to living on very dry land, and when they reached ent. The truest and most snail-like chalky districts manufactured their snails are found in greatest abundance shells, on an easy and improved princi- upon high chalk-downs, heathy limeple, almost entirely out of lime. But stone hills, and other comparatively dry others took to living in moist and bog-places; while the truest and most sluggy places, where mineral matter was like slugs are found in greatest abunrare, and where the soil consisted for dance among low water-logged meadthe most part of decaying vegetable ows, or under the damp fallen leaves of mould. Here they could get little or moist copses. The intermediate kinds no lime, and so their shells grew smaller inhabit the intermediate places. Yet and smaller, in proportion as their to the last even the most thoroughhabits became more decidedly terres- going snails retain a final trace of their trial. But to the last, as long as any original water- haunting life, in their shell at all remained, it generally cov-universal habit of seeking out the coolered their hearts and other important est and moistest spots of their respective organs because it would there act as habitats. The soft-fleshed mollusks are a special protection, even after it had all by nature aquatic animals, and nothceased to be of any use for the defence ing can induce them wholly to forget of the animal's body as a whole. Ex- the old tradition of their marine or actly in the same way men specially fresh-water existence. protected their heads and breasts with helmets and cuirasses, before armor was used for the whole body, because these were the places where a wound would be most dangerous; and they continued to cover these vulnerable spots in the same manner even when the use of armor had been generally abandoned. My poor mutilated slug, who is just now crawling off contentedly enough towards the hedge, would have been cut in two outright by my hoe had it not been for that solid calcareous plate of his, which saved his life as surely as any coat of mail. VI. A STUDY OF BONES. On the top of this bleak chalk down, where I am wandering on a dull afternoon, I light upon the blanched skeleton of a crow, which I need not fear to handle, as its bones have been first. picked clean by carrion birds, and then finally purified by hungry ants, time, and stormy weather. I pick a piece of it up in my hands, and find that I have got hold of its clumped tailbone. A strange fragment truly, with How does it come, though, that slugs a strange history, which I may well and snails now live together in the self-spell out as I sit to rest a minute upon same districts? Why, because they the neighboring stile. For this dry each live in their own way. Slugs tail-bone consists, as I can see at a belong by origin to very damp and glance, of several separate vertebræ, all marshy spots; but in the fierce compe- firmly welded together into a single tition of modern life they spread themselves over comparatively dry places, provided there is long grass to hide in, or stones under which to creep, or juicy herbs like lettuce, among whose leaves are nice moist nooks wherein to lurk during the heat of the day. Moreover, some kinds of slugs are quite as well protected from birds (such as ducks) by their nauseous taste as snails are by their shells. Thus it happens that at present both races may be discovered in many hedges and thickets side by side. but the real home of each is quite differ piece. They must once upon a time have been real disconnected jointed vertebræ, like those of the dog's or lizard's tail; and the way in which they have become fixed fast into a solid mass sheds a world of light upon the true nature and origin of birds, as well as upon many analogous cases elsewhere. When I say that these bones were once separate, I am indulging in no mere hypothetical Darwinian speculation. I refer, not to the race, but to the particular crow in person. These very pieces themselves, in their embry contrary, a long bony tail is only an inconvenience. All that they need is a little muscular knob for the support of the tail-feathers, which they employ as a rudder in guiding their flight upward or downward, to right or left. The elongated waving tail of the Solenhofen bird, with its single pair of quills, must have been a comparatively ineffectual and clumsy piece of mechanism for steering an aerial creature through its novel domain. Accordingly, the bones soon grew fewer in number and shorter in length, while the feathers simultaneously arranged themselves side by side upon the terminal hump. As early as the time when our chalk was deposited, the bird's tail had become what it is at the present day-a single united bone, consisting of a few scarcely distinguishable crowded rings. This is the form it assumes in the toothed fossil birds of Western America. But, as if to preserve the memory of their reptilian origin, birds in their embryo stage still go on producing separate caudal vertebræ, only to unite them together at a later point of their devel onic condition, were as distinct as the to the absolutely limbless serpents individual bones of the bird's neck or themselves. But to flying birds, on the of our own spines. If you were to examine the chick in the egg you would find them quite divided. But as the young crow grows more and more into the typical bird-pattern, this lizard-like peculiarity fades away, and the separate pieces unite by "anastomosis" into a single "coccygean bone," as the osteologists call it. In all our modern birds, as in this crow, the vertebræ composing the tail-bone are few in number, and are soldered together immovably in the adult form. It was not always so, however, with ancestral birds. The earliest known member of the class—the famous fossil bird of the Solenhofen lithographic stone-retained throughout its whole life a long flexible tail, composed of twenty unwelded vertebræ, each of which bore a single pair of quill-feathers, the predecessors of our modern pigeon's train. There are many other marked reptilian peculiarities in this primitive oolitic bird; and it apparently possessed true teeth in its jaws, as its later cretaceous kinsmen discovered by Professor Marsh undoubtedly did. When we compare side by side those real flying dragons, the Ptero-opment into the typical coccygean bone. dactyls, together with the very birdlike Deinosaurians, on the one hand, and these early toothed and lizard-tailed birds on the other, we can have no reasonable doubt in deciding that our own sparrows and swallows are the remote feathered descendants of an original reptilian or half-reptilian ancestor. Why modern birds have lost their long flexible tails it is not difficult to see. The tail descends to all higher vertebrates as an heir-loom from the fishes, the amphibia, and their other aquatic predecessors. With these it is a necessary organ of locomotion in swimming, and it remains almost equally useful to the lithe and gliding lizard on land. Indeed, the snake is but a lizard who has substituted this wriggling motion for the use of legs altogether; and we can trace a gradual succession from the four-legged true lizards, through snake-like forms with two legs and wholly rudimentary legs, Much the same sort of process has taken place in the higher apes, and, as Mr. Darwin would assure us, in man himself. There the long prehensile tail of the monkeys has grown gradually shorter, and, being at last coiled up under the haunches, has finally degenerated into an insignificant and wholly imbedded terminal joint. But, indeed, we can find traces of a similar adaptation to circumstances everywhere. Take, for instance, the common English amphibians. The newt passes all its life in the water, and therefore always retains its serviceable tail as a swimming organ. The frog in its tadpole state is also aquatic, and it swims wholly by means of its broad and flat rudder-like appendage. But as its legs bud out, and it begins to fit itself for a terrestrial existence, the tail undergoes a rapid atrophy, and finally fades away altogether. To a hopping frog on land, such a long train would be a useless drag, while in the water its webbed elled rudiment as a lingering reminisfeet and muscular legs make a satisfac- cence of their original habits. tory substitute for the lost organ. Last of all, the tree-frog, leading a specially terrestrial life, has no tadpole at all, but emerges from the egg in the full frog-like shape. As he never lives in the water, he never feels the need of a tail. VII. BLUE MUD. AFTER last night's rain, the cliffs that bound the bay have come out in all their most brilliant colors; so this The edible, crab and lobster show us morning I am turning my steps seaward, an exactly parallel case among crusta- and wandering along the great ridge of ceans. Everybody has noticed that a pebbles which here breaks the force of crab's body is practically identical with the Channel waves as they beat against a lobster's, only that in the crab the the long line of the Dorset downs. body-segments are broad and compact, Our cliffs just at this point are comwhile the tail, so conspicuous in its posed of blue lias beneath, with a capkinsman, is here relatively small and ping of yellow sandstone on their sumtucked away unobtrusively behind the mits, above which in a few places the legs. This difference in construction layer of chalk that once topped the depends entirely upon the habits and whole country-side has still resisted the manners of the two races. The lobster slow wear and tear of unnumbered cenlives among rocks and ledges; he uses turies. These three elements give a his small legs but little for locomotion, variety to the bold and broken bluffs but he springs surprisingly fast and far which is rare along the monotonous through the water by a single effort of southern escarpment of the English his powerful muscular tail. As to his coast. After rain, especially, the big fore-claws, those, we all know, are changes of color on their sides are often organs of prehension and weapons of quite startling in their vividness and inoffence, not pieces of locomotive tensity. To-day, for example, the yelmechanism. Hence the edible and low sandstone is tinged in parts with a muscular part of a lobster is chiefly to deep russet red, contrasting admirably be found in the claws and tail, the lat- with the bright green of the fields above ter having naturally the firmest and and the sombre steel-blue of the lias strongest flesh. The crab, on the other belt below. Besides, we have had so hand, lives on the sandy bottom, and many landslips along this bit of shore, walks about on its lesser legs, instead of that the various layers of rock have in swimming or darting through the water more than one place got mixed up with by blows of its tail, like the lobster or one another into inextricable confusion. the still more active prawn and shrimp. The little town nestling in the hollow Hence the crab's tail has dwindled away behind me has long been famous as to a mere useless historical relic, while the headquarters of early geologists; the most important muscles in its body and not a small proportion of the peoare those seated in the network of shell ple earn their livelihood to the present just above its locomotive legs. In this day by "goin' a fossiling.” Every case, again, it is clear that the appendage child about the place recognizes amhas disappeared because the owner had monites as snake-stones;" while even no further use for it. Indeed, if one the rarer vertebræ of extinct saurians looks through all nature, one will find have acquired a local designation as the philosophy of tails eminently simple "verterberries." So, whether in search and utilitarian. Those animals that need them evolve them; those animals that do not need them never develop them; and those animals that have once had them, but no longer use them for practical purposes, retain a mere shriv of science or the picturesque, I often clamber down in this direction for my daily stroll, particularly when, as is the case to-day, the rain has had time to trickle through the yellow rock, and the sun then shines full against its face, to |