COMPARATIVE AXATu.MY. 



215 



which wo are passing ; decline \ and change | and loss, /ollom ' decline I 

 and chttnj* | and low || in such rapid lucoeiuiou, that we can almost 

 catch tho found of universal wasting, and hear the work of dwolaium ' 

 going on biuili/ ' around us. " Tho mountain | falling || oomoth to 

 Might, and the rock | is removed out of his place. The water* \ wear the 

 itoiuf, the things which grow out of the dust of the earth \\ ore washed 

 awty, and the hop* of man | is destroyed." Conscious ' of our own iiuta- 



A,. look about ' for something to rial on; but wo look ' in txttn. 



The hearens ' and the earth | had a beginning, and they will have an 



..! tho world | is changing, ddily aud hourly. All ' oni- 



, row old aud die. The rocks \ crumble, the tree* \ fdU, 



I.; and tlio grass \ withers. The cloud* | aro flying, and the 



water* | KTO flowing awdy from us. 



icorfcs of mln, too, are gradually giving tody : the ivy \ 

 clings to tho iiionM. riii : i I.'.IIYI-, tho trier | hangs out from the shattered 

 .if.: I tli.- wall-flower | springs from the disjointed stones. The 

 founders \ of these perishable works || have shared the tame fait \ long 

 a-jo. If we look back to the days of our ancestors, to the men | as well 

 *s the duelling* | of former times, they become immediately associated 

 in ..in- imaginations, and only moke the feeling of instability sirongerand 

 deeper than before. lu the spacious domes, which onoe held our/dlhers, 

 the serpent | hisses, and the wild bird | screams. The halls, which once 

 were crowded ' with all that taste \ and science | and labour | could pro- 

 cure, which resounded with melody, and were lighted up with beauty, aro 

 buried | by their own ruin*, mocJted | by their oicn desolation. The voice 

 of merriment, and of trailing, the steps of the busy ' and the idle || have 

 closed in the deserted courts, and the weeds j choice the Entrance*, and the 

 long grass || wares upon the hearth-stone. The works of art, the forming 

 hand, the tombs, the very ashes they contained, are all gone. 



While we thus walk ' among the ruins of the post, a sad feeling of 

 insecurity I comes over us; and that feeling ' is by no means diminished || 

 when we arrive at home. If we turn to our friends, we can hardly 

 speak to them || before they bid us farewell. We see them for a few 

 wu'iments, ' and in a few moments more their countenances ' are changed, 

 and they are sent awdy. It matters not ' how near ' and dear they are. 

 The ties which bind us together || are never too close- ' to be parted, or 

 too strong ' to bo broken. Tears ' were never known to move the king of 

 tirrors ; neither is it enough ' that we are compelled to surrender one, 

 or tied, or many of those we love ; for though the price is so great, we 

 buyno/uuour with it, and our hold ' on those who remain | is as slight 

 as aver. The shadows || all | elude our grasp, and follow one another ' 

 down the valley. We gain no confidence, then, no feeling of security, by 

 turning to our contemporaries and kindred. We know ' that the forms 

 which are breathing around us, are as shortlived ' and fleeting ' as 

 those were, which have been dust ' for centuries. The sensation of 



. uncertainty, and ruin, is equally strong, whether we muse on 

 what has long been prostrate, or gaze on what is falling now, or mil fU ' 

 so soon. 



If everything | which comes under our notice || has endured for so 

 short a time, aud ' in so short a time | will be no more, we cannot say | 

 that we receive the least assurance || by thinking on ourselves. When a 

 /<.. more friends | have Uft, a/eir more hopes | deceived, and a/ew more 

 changes | mocked us, "we shall be brought to the grave, aud shall 

 remain in the tomb : the clods of the valley shall be sweet unto us, and 

 every man ' shall fottoic ns, as there are innumerable ' be/dre us." .411 

 power ' will have forsaken the strongest, and the lo/liest ' will be laid low, 

 and every ey ' will be closed, and every voice ' hushed, and every heart ' 

 will have ceased its beating. And when we have gone ' ourselves, even our 

 memories ' will not stay behind us long. A few of the near and dear || 

 will bear our likeness ' in their bosoms, till they ' too ' have arrived ' at 

 the end of their journey, and entered the dark dwelling of unconsciousness. 

 In the thoughts of dthers || we shall live ' only till the last sound of 

 the bell, which informs them of our depdYture, has ceased to vibrate in 

 their ears. A stono, perhaps, may tell some wanderer where we lie, when 

 we came here, and u-ht'n we went awdy ; but ' even that | will soon re/use 

 to bear us record; "time's effacing fingers" \ will be busy on its surface, 

 and | at length ' will wear it smooth ; and then | the stone itself | will 

 nnfc, or criimble, and the wanderer of another age | will pass, without a 

 .tingle call ' upon his sy'mpathy, over our unheeded graves. Greenwood. 





COMPARATIVE ANATOMY. VI. 



ECHINODEEMATA (HEDGEHOG-SKINNED ANIMALS.) 



FROM the earliest times, before Aristotle wrote of animals, the 

 great similarity in outward appearance between the hedgehog 

 when rolled up in self-defence, and the sea-egg, or echinus, has 

 been so recognised as to cause them to be called by the same 

 name. In Greek, echinus (x"*) means both the one and the 

 other. In English, we have expanded this superficial association 

 to include the young of our own species when they have arrived 

 at that age when they are always in mischief, and when, ac- 

 cording to the notions of a past generation, they were always to 

 be cuffed, because, if they did not deserve it at tbe time oi 

 the infliction, they soon would do so. 



With regard to the English automation not much is to t 

 said, because, while the human urchin is actively mischievous, 

 and often made to smart for it, panaively, tbe other urchin* 

 are very harmless except in passive self-defence. Tbe other 

 resemblance, though misleading anatomically, ii very "*'^. on 

 account of the dense covering of sharp spines sticking oat in all 

 directions, matted and crossing one another like the spinet 

 of the thistle leaf ; and also on account of the globular form, 

 which, though temporary in the land urchin, is permanent in th* 

 echinus. 



The shell of a typical echinus, upon which the spines are set, 

 is a round box of very complex and beautiful structure. It 

 consists of plates of carbonate of lime so closely and accurately 

 fitted together, that, even after the spines have been stripped off, 

 it requires minute examination to discover the lines of division 

 between them. Tbe box has the form of a more or leu de- 

 pressed sphere, varying from the shape of a true globe to that 

 of a Turkish turban. At the two poles of the box are two holes s 

 that which opens on the under side of the animal is the mouth, 

 while that which is found at the centre of the top side is the 

 other end of the food canal. A further examination reveals 

 that the shell is made up of five similar radial divisions, which 

 stretch from pole to pole, and may be thus described : The 

 central zigzag line, running from mouth to anus, has on either 

 side of it a row of small plates alternating with one another; and 

 on the outer side of each of these rows of plates is a row of small 

 holes. There are six of these holes in each plate. Externally 

 to these perforated plates are situated two other rows of larger 

 plates, one on each side, and these are united at their external 

 edges to the next radial division of the box by a zigzag line. 

 The outer side of both the perforated plates and the plates 

 without holes are covered with bosses, each of which has a more 

 prominent rounded knob projecting from the top of it, which 

 knob has a pit in its centre. These knobs bear the spines. 

 They are of various sizes, but so arranged as to form a beauti* 

 fully regular pattern ; for each plate has at its centre a large 

 boss, and, as the plates are regularly placed one above the 

 other, there are, on the whole shell, twenty rows of these 

 tubercles running from top to bottom, set on lines which corre- 

 spond to the meridians of a globe. Yet, if the reader has 

 followed the description, he will see that these rows are not all 

 at equal distances from one another, for those on the smaller 

 perforated plates are approximated, while those of the larger 

 plates are removed from one another; nor are the tubercles 

 of the several rows all at the same distance from each other. 

 Besides these tubercles, a great many others of very various 

 sizes lie between the rows. The whole effect of the pattern is 

 very beautiful, and shows that symmetry without sameness, 

 that unity in variety, with which all the works of God abound, 

 and which the architect and the designer are so perpetually 

 striving after, but to which they so seldom attain. 



The ten perforated tracts which, being arranged in pairs, form 

 five double bands or courses, converge towards the month and 

 anus. The regularity of these tracts, converging at both ends 

 and leaving between them a solid tract, has suggested a fanciful 

 analogy. They were thought to resemble the gravel walks of 

 our gardens, with their borders or avenues of trees on each side, 

 and so were called ambulacra; ambulacrum being a post-classical 

 Latin word, meaning a garden walk. At the point where the two 

 converging perforated tracts unite, is a single six-sided solid plate, 

 which has at its side nearest the ambulacra a hole from which 

 the ambulacral holes seem to diverge. The five perforated hexa- 

 gonal plates which thus stand at the end of the ambulacral 

 avenues, are separated from one another and from the top open* 

 ing by five other irregularly eight-sided plates which surround 

 the small movable scales which cover in the anus. As far as 

 our previous description has gone, the reader will perceive that 

 all the parts are perfectly radial. The five segments are abso- 

 lutely alike ; but one of the eight-sided plates has, between the 

 large pore and the anus, a space which is full of a great 

 multitude of holes, and in this respect it differs from all the 

 other five plates of the series, and is called the madreporio 

 plate. At the other pole of the body there is a large opening 

 covered by a leathery membrane, in Mie centre of which is the 

 mouth. Placing the animal with its month downwards, which 

 is the position it usually occupies, and looking at it from above, 

 let us enumerate the perforations which we have described, 

 beginning from the centre at top, and proceeding outward and 



