Apbii. 1, looir 



KNOWLEDGE 



83 



BracIiysUhiia, aud a Ceropeffia, are cited, all of which 

 possess edible tubei-s. 



The Comjites Beiidus for Fel>riiary 11th contains an 

 interesting paj^er hv M. Bernard, eatitled " Sur la tiiber- 

 culisation de la Pouinio de terre," in which it is shown 

 that the potato-tuber is produced bv the action of a fiiiiijus, 

 Fitsariiim SoliDii. This fimgus is always present in the 

 tubers, whether healthy or diseased, and attacks the 

 growinjj subterranean stems, inducing, it is supposed, the 

 arrest of their growth and the development of the tubers. 

 — S. A. S. 



Cyclones. — At the meetiusj; of the Eoyal Society of 

 Edinburgh on March Ith, Mr. John Aitken, f.r.s., contri- 

 buted some additional notes to his paper on " Dynamics 

 of Cyclones aud Anticyclones," read a year ago. He was 

 of opinion that cyclones are found over those parts of the 

 earth where there is a high temperature. The movement 

 of the storms in our own area is in a north-easterly direc- 

 tion, because the winds on the north-west side of the 

 anticyclones were generally stronger than those on the 

 other sides. The cyclone is formed out of air from the 

 south travelling towards the north and rotating at a 

 greater rate of velocity than the surface of the earth. He 

 asked: "What is a cyclone?" aud answered his question 

 by sayiug that it is caused by hot air ascending and drawing 

 in air all around it, that it is formed by the anticyclone, 

 and that it is on the north-west side of the anticyclone 

 that we get the strongest winds. The general theory is that 

 a cyclone is not an independent power at all, but is simply 

 a large eddy produced by the action of two anticyclones. 

 Cyclones may be divided into couvectional and dynamical, 

 and the distinction may be explained in this way. If the 

 cyclone is couvectionally driven, the currents move towards 

 the centre, but if dynamically driven they will move s])irally 

 outwards. The exhaustive investigations made at Wash- 

 ington show that the general tendency is inwards, and, 

 further, that in convectionally-driven cyclones the velocity 

 increases towards the centre, but when dynamically driven 

 the velocity does not increase. Mr. Aitken also spoke of 

 the great storm tracks from America, the one passing to 

 the north of the British Isles, aud the other to the south ; 

 and of how at certain seasons the one moved southwards 

 and the other noi'thwards, aud so decreasing the inter- 

 vening space aud vice versa. However powerful an anti- 

 cyclone might be, a vast amount of energy is without 

 doubt developed in the cyclone itself ; but the cyclone is 

 governed to a very large extent by the anticyclone. At 

 Washington it is held that the anticyclone is much the 

 more powerful of the two. It has also been ascertained 

 that they sometimes extend to 6^ miles, although formerly 

 it was thought they were much thinner. Professor Dobbie 

 held that a cyclone was a vast eddy between two currents 

 — the polar aud the equatorial — but that view is somewhat 

 modified now. In all cyclones one side is dry and cold, 

 and the other moist and warm ; the reason being that the 

 cyclone sweeps before it all the warm surface air and 

 brings down i?i its wake higher, and therefore drier and 

 colder, air. As there is greater violence of winds in 

 cyclones than in anticyclones, there must be some strong 

 source of energy in the cyclonic areas. It is still evident 

 that to a great extent " the wind bloweth where it listeth. 

 aud no one can tell whence it cometh and whither it goeth," 

 as was said two thousand years ago. Yet, as Mr. Aitken 

 has been able to calculate the particles of dust in the air, 

 which were considered to be " numberless," he may yet be 

 able to lay down some sound general laws for the regula- 

 tion of the cyclones and anticyclones to which he has for 

 some time been giving his valuable attention. — J. G. McP. 



ENTOMOLOoicvi. — Professor Wheeler's observations on 

 .American "driver" ants and their "guest" beetles 

 (mentiouod in Knowledge for February, pp. 32-3), 

 have been followed by the I'ublication of a valualjle paper 

 on the same subject by Fat her Wasinann, in the ZooIck/. 

 Jahrh. (abf. f. Sijst. ii.s.ir.), XIV., 1900, pp. 21 0-28!), pi's. 

 13, 11). The inquilines described in this papor arc rove 

 beetles (StaphyiinidiE). A new genus, £cito<ja4er, found 

 in the nests of a Brazilian EcUon. is believed to live in 

 comjdete harmony with the ants and to" be fed from their 

 mouths. In return the beetles provide their hosts with 

 an oily food-substance secreted by fat-cells beneath the 

 cuticle of the abdomen, Ecitocjaster is quite nnlike the 

 ants in appearance, but the beetles of another new (allied) 

 gentis, Ecitopliija, closely mimic the large workers of 

 Ecifon foreli (in whose company they live), not only in 

 form (see p. 33 ante) but also in colour. These workers 

 have simple eyes, and presumably therefore a colour-scuse. 

 The African driver-ants (Anoiniiia) harbour guest-beetles 

 referred to a new genus Syinpoleinon, which seem to bear 

 the same relationship to them as Ecitogaslcr to Eciloti. 

 A very wonderful adaptation in these beetles is the j^re- 

 sence of two deep longitudinal grooves on the forebody 

 shield (pronotum), affording hold for the mandibles of the 

 ants and enabling them to carry the beetles with them on 

 their expeditions. Comparing the guest-beetles of the 

 driver-ants in the Neotropical aud Ethiopian regions, 

 Father Wasmauu points out the analogy between the 

 types of iuquiline which have been developed both in the 

 Eastern and in the Western Continent. Comparing the 

 guest-beetles of the South American with those of the 

 North American Ecitons. he concludes that the symbiosis 

 is less highly developed in the latter, and that the beetles 

 have not therefore accompanied their hosts from the south, 

 but have adapted themselves to an inquiliue life since the 

 ants immigrated into North America. — G. H. C. 



Zoological. — The shoe-bill or whale-headed stork 

 {Balxniceps rex), ever since its discovery by Mansfield 

 Parkyns on the White Nile in I841>, has e.xcited great 

 interest. In 1860 Peth^-ick brought home two live si)eci- 

 meus, which were exhibited in the Zoological Gardens and 

 attracted much attention by their singular aspect. Out- 

 wardly the bird is chiefly remarkable on account of its 

 enormous bill, which is shaped somewhat like the head of 

 a whale, hence one of its names, but it is in other resjiects 

 distinctly weird-looking, having a gaimt grey body, long 

 legs, and a large head surmounted by a little curled tuft, 

 and a scowling expression of the eyes. It has many struc- 

 tural peculiarities which anatomists have had few oppor- 

 tunities of examining owing to the great rarity of the bird 

 in collections. The British Museum, for instance, up to 

 a few months ago only possessed one skin. The bird itself 

 is sufficiently numerous in the great marshes of the White 

 Nile south of Fashoda, but it is extremely shy and difficult 

 of approach. Since otir reconquest of the Soudan several 

 specimens have been obtained on the tributaries of the 

 White Nile, while juist lately Sir Harry Johnston has sent 

 to the British Museum a specimen of the bird shot, at 

 Entebbe, on the north shore of Lake Victoria, East Africa. 

 Great interest attaches to this specimen, which is now on 

 exhibition in the British Museum, because hitherto the 

 only known locality for the shoe-bill was the White Nile, 

 to which river it seemed to be entirely, confined. 



At a recent meeting of the Linnean Society, Prof. 

 E. Kay Lankcster read a paper on the systematic 

 position of Jiluropus vielanolcucus, with notes on itvj 

 osteology by Mr. Lydekkcr. The animal in question is 

 an inhabitant of eastern Tibet, and has hitherto been 

 very generally regai-ded by English zoologists as an 



