152 



KNOWLEDGE 



[July 1, 1895. 



Palreozoic types are almost as highly specialized as their 

 esisting descendants, and thus showing that we should 

 have to go much further back before we reached the 

 ancestral type. With the exception of certain cockroach- 

 like insects, which occur in the middle Silurian, the 

 scorpions are indeed the oldest land animals, and are 

 therefore entitled, in spite of their unpleasant propensities, 

 to our utmost respect. 



We have said that in Paleozoic times there existed a 

 south equatorial land-girdle, distinguished from the land 

 of the northern hemisphere (from which it was probably 

 isolated) by the peculiar character of its fauna ; and as the 

 PaL'eozoic scorpions inhabited the northern land, it is 

 scarcely likely that they were also found in the southern 

 zone. Early in the Secondary epoch the latter zone 

 appears to have been split up, and the continental areas 

 consequently assumed some approach to their present 

 configuration. The descendants of the ancient Palfpozoie 

 scorpions began soon after, in all probability, to migrate 

 southwards, along the different lines of communication ; 

 and we thus can readily understand why some of the 

 existing sub-families are represented in such widely 

 separated areas as India, Africa, South America, and 

 Australia, without resorting to any comparatively recent 

 connection between these countries. In this connection it 

 is important to notice that the South American and African 

 scorpions belong to distinct genera. 



If such an explanation holds good in the case of the 

 scorpions, there is no reason why it should not be equally 

 valid in the instance of Pcripatus. It may be objected 

 that, whereas in the case of the scorpions we have only 

 mh-fainHies which occur over such widely sundered areas, 

 in Pcripatus we have one and the same genus. The 

 objection would, however, be equally valid if we assumed 

 that genus to have attained its present geographical dis- 

 tribution by the aid of a southern band of land, seeing 

 that there is no evidence that such a tract has existed since 

 the end of the I'alasozoic or the commencement of the 

 Secondary epoch. '■ 



Although not coming strictly within the scope of its title, 

 this article may be concluded by a brief reference to some 

 of the habits of scorpions. All scorpions are nocturnal 

 and somewhat sluggish creatures ; but while some species, 

 in which the tail is light, carry it stretched nearly straight 

 out behind, those in which it is heavier habitually curve it 

 over the back ; and those forms in which the appendage 

 is carried in the latter manner are further distinguished by 

 raising their bodies much higher on the legs than is the 

 case with the others. Some kinds, again, when walking, 

 carry their large pincers stuck out in front of the head to 

 act as feelers. All scorpions are carnivorous, while many 

 of them, in spite of their sluggish appearance, are able to 

 capture and kill such alert creatures as cockroaches. Mr. 

 Pocock, who has kept scorpions in captivity, writes that 

 "as soon as a cockroach is seized, the use of the scorpion's 

 tail is seen, for this organ is brought rapidly over the 

 latter's back, and the point of the sting thrust into the 

 insect. The poison instilled into the wound thus made, 

 although not causing immediate death, has a paralyzing 

 effect upon the muscles, and quickly deprives the insect of 

 struggling powers, and consequently of aU chance of escape. 

 If the insect is a small one — one in fact that can be easily 

 held in the pincers and eaten without trouble while alive — 

 a scorpion does not always waste poison upon it. Thus I 

 have seen a Parahuthm (one of the genera of scorpions) 



* It may be well to state that there are many fatal objections to the 

 th"orv of an Antarctic continent, which united Soutli America, 

 Africa, and Australia, having existed in Tertiarv times. 



seize a bluebottle fly, transfer it straight to its mandibles, 



and pick it to pieces with them while still kicking 



An insect is literally picked to pieces by the small chelate 

 mandibles, these two jaws being thrust out and retracted 

 alternately, first one and. then the other being used : the 

 soft juices and tissues thus exposed being drawn into the 

 minute mouth by the sucking action of the stomach." 



Old fables die hard, and none is more persistent than 

 the legend that the scorpion, when surrounded by a 

 ring of fire, puts an end to its existence by turning its tail 

 over its back and stinging itself to death. No matter that 

 naturalists have proved that their poison is innocuous to 

 their own kind, and that scorpions are killed by a very 

 moderate elevation of temperature, the old, old story is still 

 as firmly believed as ever by the general public. 



In an article published in the last edition of the 

 Ennjclopcedia Britannicn, the Rev. 0. P. Cambridge refused 

 to believe that there was any substratum of fact in the 

 popular legend, but Mr. Pocock, writing in Nuturc for 1893, 

 is more merciful. He thinks, indeed, that a scorpion may 

 occasionally sting itself, either by a random blow meant for 

 an unseen enemy, or when it has been irritated by the contact 

 of any strong stimulant, such as acid or mustard, or even 

 that in the madness of pain it may be driven to turn its 

 weapon on itself : but that in any case there is any 

 intention of causing its own death cannot for a moment be 

 admitted. 



Although, probably, many of my readers are acquainted 

 with it, for the benefit of those who are not, I must conclude 

 with a well-known Indian story. Where scorpions and 

 centipedes abound, it is the general custom of servants in 

 India to turn their master's boots upside down before 

 helping to put them on. In the instance in question, where 

 this precaution had been omitted, a cavalry officer had just 

 put his foot into a regulation boot, when he felt something 

 sharp touch his heel ; with the greatest promptitude he 

 lifted his leg and stamped violently on the ground in the 

 hope of destroying the supposed scorpion before it had time 

 to use its sting. He found that a spur, with the rowels 

 uppermost, had been inadvertently dropped into the boot ! 



SOME PLANETARY CONFIGURATIONS. 



By Lieut. -Col. E. E. Makkwick. 



THE aspect of the planets in the sky at any given 

 time has always been an interesting subject, and 

 was one of the most important branches of the 

 Old World astronomy. The Egyptians, Chaldseans, 

 Babylonians, Greeks, and other ancient peoples 

 studied the heavens by naked-eye observation, ages before 

 the invention of the telescope, and the varying positions 

 of the planets must have been well-known phenomena 

 to them. Why, more than to us in England in the 

 nineteenth century ? They could see these things under 

 much more favourable circumstances. 



Firstly, because in their latitude — say about 36° N. as 

 a mean — the equator, where it cuts the horizon, is tilted up 

 at an angle of 54°, and hence, even supposing that the 

 conditions of seeing were the same as ours, the planets 

 — being confined within certain limits north or south of 

 the equator — must be first seen in the evening at a higher 

 altitude than in a latitude where that circle slopes at a 

 less angle to the horizon. This is illustrated in Fig. 5, 

 which shows a portion of the equatorial belt, 47' wide, 

 within which Mercury and Venus are confined relatively to 

 the sun. The orbits of Mercury and Venus being interior 

 to that of the earth, and inclined to the ecliptic, they can 



