JcsE 22, 1883.] 



♦ KNOWLEDGE ♦ 



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V AN aL'iL3l714,TED \Jlf- ^ 



^MACAZlNEo?5Gi£NCE^ 



PLAINLY'^'CRDED-EXACTlVrESCRlBED . 



LONDON: FRIDAY, JUNE 22, 1883. 



Contents of No. 86. 



PAGE. 



A Xaturalist's Tear ; Concerning 



Bsta. By Grant Allen 36" 



'Sociable'* Tricycles. By John 



Bn 



368 



The Ori;r>t. of Whales. By B. A. 



Proctor 369 



The Chemistrv of Cookery.— XII. 



By W. M. Williams 370 



Laws of Briehtness.— IV. (JlUu- 



tralej) Bv R. A. Proctor 372 



Australian Ants 373 



viei. 



Sun Views of the Earth (////«- 



trated.) By R. X. Proctor 375 



Limits of Telescopes 375 



Editorial Oossip 376 



Reviews : — Ijintern Headings — The 



Electrii- I.iu'lit 378 



The Face of the Sty 379 



Correspondence 380 



Our Mathematical Column 381 



Our Chess Column : 

 The International Tonmament ... 382 



A NATURALIST'S TEAR. 



By Graxt Allek. 



XV.— COXCERXIXG BATS. 



"IT^HAT a number of wild aiaimals we possess in 

 * * England whose very existence hardly ever obtrudes 

 itself upon us, even though they may have taken up their 

 residence in the self-same houses which wo conceited 

 human beings vainly presume to call our own. For 

 example, there are the bats. They say no less than 

 fourteen distinct species of these queer, night-flying 

 creatures have been found in Britain, and yet how seldom 

 anybody ever notices them, save by the merest chance — 

 certainly far too casually to venture upon pronouncing a 

 definite opinion on the obscure question of their specific 

 distinctness. In the garret of this very house, now, 

 between the outer tiles and the plaster ceiling, a whole 

 colony of the long-eared kind — commonest V)ut one, I 

 should say, among the British species — has taken up its 

 permanent quarters. We are but five " humans " in 

 precarious possession of the premises, but when we first 

 came here we found the bats already firmly settled on the 

 spot, ranged up from the rafters liy dozens, and hanging 

 head downward by their hooked claws from the edges of 

 the cross-beams or other timbers. Recognising their just 

 prescriptive claim against uncompensated disturbance, we 

 have left them still strictly as tenants in capiti' ; and every 

 summer night about half past nine, they issue forth from 

 the attic air-hole, to sweep the garden far and wide in 

 search of moths and other nocturnal insecta During the 

 winter, however, they lay by quietly in cosy crannies 

 between the tiles, hibernating after the fashion of most 

 smaller British mammals, and living on the store of fat 

 which they have duly accumulated on their own plump 

 bodies in the lavish abundance of the flush season. 



Bats are, perhaps, the oddest and most abnormal of all 

 mammals, with their very developed wing-like membranes, 

 and their extraordinary power of extended flight. Yet it 

 is not verj- difficult to trace by analogy the steps through 

 which they have acquired their existing organs of locomo- 

 tion. True, the great central group of mammals from 



which they appear to be descended — the insectivores, or 

 shrew and mole group — are particularly wanting in any- 

 thing approaching the possession of flight ; they are 

 thoroughgoing ground animals, most of them burrowers, 

 and all of them averse to climbing, which seems invariably 

 the first step towards the acquisition of wings, or their 

 equivalent. This, however, is doubtless due to the very 

 fact that their more advanced and developed descendants, 

 the bats, have cut them out in this respect, so that all the 

 intermediate and less perfect types have long since become 

 extinct But the various half-flying creatures which we meet 

 ^\-ith elsewhere, though not themselves at all connected 

 genetically (save, perhaps, in one case) with the bats or the 

 insectivores, still help us to understand by analogy the origin 

 of the bat tribe from an ordinary insectivorous ancestor. 

 It is well known that among forestine animals a great ten- 

 dency exists towards the production of a rudimentary 

 flying apparatus ; and there is hardly any great gi-oup of 

 mammals among which themoretree-haunting members have 

 not begun to develop such a mechanism, in a more or less 

 perfect form. Anybody who has ever watched even our 

 English squirrels, leaping lightly from bough to bough, can 

 readily understand how closely their movements approxi- 

 mate to the rudest type of flight ; for in these familiar 

 creatures, which have as yet no specialised membrane for 

 the purpose, there is some taint approach towards the use 

 of a parachute, as they always spread out their legs, head, 

 and bushy tail to the utmost extent in taking what is 

 characteristically described as " a flying leap." But among 

 some of their relations, the whole class of flying 

 squirrels, comprising a number of American and Asiatic 

 forms, there has been developed a distinct e.xtensible 

 membrane or fold of skin, spreading from the fore- 

 legs to the hind-legs, and employed as a parachute 

 to break the creature's fall, or to permit it to glide 

 obliquely from one bough to another at a lower level. 

 Naturally, the possession of such a membrane gives an 

 arboreal animal a great advantage in the struggle for 

 existence, and hence it is frequently found, independently 

 developed over and over again, amongst all great tribes of 

 tree-haunting animals. For example, among the rodents 

 themselves, there is another group besides the flying- 

 squirrels in which the same peculiarity appears under 

 similar circumstances, and that is in the African family of 

 the anomalures — a family closely resembling the flying- 

 squirrels in outer appearance, but difTering from them in 

 so many points of internal structure that they must be 

 looked upon as distinct in origin, and owing their external 

 similarity rather to likeness of circumstances than to 

 identity of genealogical descent They help, in fact, to 

 prove the universal rule, that nearly the same conditions 

 produce everywhere nearly the same results. 



Among the marsupials, or pouched animals, again, the 

 very arboreal family of the Phalangers has produced 

 several so-called flying species, one of which is even known 

 locally in Australia as the flying squirrel, though, of 

 course, it is not really connected in any way with the true 

 rodent squirrels. Nevertheless, the resemblance Ln the 

 bushy tail, the long, loose, flying membrane, and the whole 

 shape of the head and body, is so close as to be almost 

 ridiculous. Finally, there is one very strange creature — 

 half lemur and half insectivore,the colugo or galeopithecus 

 — which seems like an actual remnant of the ancestral 

 line by which at least one great group of bats — the fruit- 

 bats of the East — were originally evolved. This curious 

 beast, a surviving representative of some very ancient 

 type, differs from most other parachute-bearing mammals, 

 in the fact that the space between its fingers is " webbed," 

 or covered with skin, a great approximation to the 



