October 29, 1903] 



NATURE 



623 



A Little-known Peculiarity of the Hamadryad Snake. 



A STRUCTURAL peculiarity of the " king cobra " which I 

 have recently ascertained while studying the anatomy of 

 the Ophidia seems to me to be so rernarkable that it must 

 have been noticed in such comprehensive works as Bronn's 

 " Thierreich " and Dr. Gadow's account of serpents in the 

 " Cambridge Natural History " were it known. I venture, 

 therefore, to give a short account of the matter without 

 professing to have made an exhaustive survey of the liter- 

 ature of the group. The windpij>e of this snake opens, as 

 usual, not far from the heart into the lung, which presents 

 no remarkable divergencies from the lungs of other snakes ; 

 it is in the same way functional as a lung for the first half, 

 and becomes a mere thin-walled air bag posteriorly. 

 Before opening into the lung, however, the trachea is con- 

 nected with a long series of approximately equi-sized air 

 sacs in the neck, which follow close upon each other, and 

 entirely occupy the neck down to the region where the 

 heart lies. These sacs are so closely adpressed that the 

 appearance given is that of a series of septa, dividing the 

 space surrounding the windpipe and gullet into meta- 

 merically arranged compartments. I thought at first, in 

 fact, that I had been able to observe a segmentation of the 

 coelom in this region quite analogous to that of an annelid. 

 Each cavity, however, is continuous with the interior of the 

 windpipe by an oval and clearly defined orifice on its lower 

 surface. These apertures are regular and of fairly equal 

 size, and give to the windpipe quite the appearance of a 

 fiute. There are a large number of them, thirty to forty. 

 There is no question here of pathological conditions or of 

 accidental cuts. The regularly disposed series of sacs into 

 which they open negatives anything of the kind. They are, 

 I suppose, an extreme modification of what the late'Prof. 

 Cope termed the " tracheal lung " in Chersydrus and other 

 snakes. The most obviously comparable structure that I 

 can think of for the moment is the ventral slit in the wind- 

 pipe of the emu, which similarly opens into a thin-walled 

 sac. This is believed to be connected with the singular 

 " drumming " sound emitted by that bird. Perhaps some 

 of your readers who are acquainted with the Hamadryad can 

 inform me as to a possible "voice," or whether it can 

 produce a varied or especially prolonged hiss. I propose to 

 offer a more detailed account of the structure of the wind- 

 pipe and other organs of this snake to the Zoological Society 

 as soon as possible, Frank E. Beddard. ' 



weather, the ring is distinct, and measurements made here 

 some time ago gave 26° as the radius of the whitish haze 

 and 5° more for the reddish border, indicating that its 

 visible extension was greater even than on Mont Blanc. 



M. Forel states that he has seen a coloured circle 

 surrounding the sun since the first of last August. The 

 fact of it not having attracted notice previously in Europe 

 would seem to show either that the clearer atmosphere of 

 the United States favours its perception, or that the micro- 

 scopic dust in the upper air, which is supposed to produce 

 the diffraction phenomenon, preponderates above this 

 country. The last hypothesis is supported by the fact that, 

 from the proximity of the West Indian volcanoes, the fine 

 dust ejected by them during the eruptions that year may 

 have drifted northward, before making a circuit of the 

 globe, and a larger quantity may still remain suspended 

 in the rarefied atmosphere above the eastern United States 

 than exists over Europe. A. Lawrence Rotch. 



Blue Hill Meteorological Observatory, Massachusetts, 

 U.S.A., October 14. 



The New Bishop's Ring. 

 Regardi.vg M. Forel's suggestion (see Nature, p. 396) 

 that persons ascending to considerable altitudes should 

 observe whether the ring around the sun, which was so 

 noticeable a phenomenon after the diffusion of the volcanic 

 dust from the Krakatoa eruption in 1883, is again visible, 

 I beg to say that, before reading his letter in La Gazette 

 dc Lausanne, I had noted the ring on August 20 from 

 the Montanvert, near Chamonix, at an altitude of 6300 feet. 

 The day was exceptionally clear, and when a peak hid the 

 sun itself, the whitish glare fringed with reddish brown 

 that surrounded it attracted my attention. Being upon the 

 summit of Mont Blanc (15,780 feet) on September i, in clear 

 weather, f again observed the ring, which, however, was 

 no better defined than lower down on the mountain, not- 

 withstanding the circumstance that the dark blue sky 

 furnished an excellent background. Angular measurements 

 there showed that the radius of the visible outer limit of 

 the reddish ring was between 20° and 25°. 



While the phenomenon was not again seen by me last 

 summer m Europe, it has often been observed during the 

 past year here at my observatory, elevated only 640 feet 

 above the sea, and an article in Science of January 23 

 by my assistant, Mr. Clayton, describes the reappearance 

 of this second " Bishop's ring " and the accompanying 

 brilliant sunsets during the early part of last winter. Sub- 

 sequently, the ring was observed in January and February 

 and also in May, June, and July, when highly coloured 

 and prolonged afterglows followed the sunsets towards the 

 close of the latter month. During the first part of August 

 the ring was seen on clear days, and during September the 

 vivid yellow colour of the western sky, persisting some- 

 times more than an hour after sunset, was frequently re- 

 corded. To-day (October 14), after a period of rainy 

 NO. 1774, VOL. 68] 



The Nervous System of Anodonta cygnea. 



The supra-oesophageal ganglion of Anodonta is usually 

 regarded as representing both the cerebral and pleural 

 ganglia, and is commonly spoken of as the " cerebro- 

 pleural." Prof. Howes mentions in his " Atlas " that Prof. 

 M. Hartog has occasionally observed a ganglionic swelling 

 on one or both of the cerebro-visceral connectives in front 

 of the pericardium, but that he himself has failed to find 

 any such enlargement. In view of the doubt that exists, it 

 seems to be worth recording that yesterday one of my pupils, 

 A. C. Roxburgh, while dissecting an Anodonta in the 

 Charterhouse laboratory, exposed a well-developed ganglion 

 of the usual orange colour, upon the left connective in the 

 e.xact position mentioned by Prof. Hartog. Microscopical 

 examination removed all doubt as to the nature of the swell- 

 ing, for numerous ganglion-cells were easily recognised in 

 the teased preparation. It is thus probably more correct 

 to term the anterior ganglion " cerebral " rather than 

 cerebro-pleural. Perhaps some of those who are better 

 equipped for research than is possible or advisable for those 

 engaged in elementary laboratories might find it worth 

 while to examine series of sections of the connective at 

 this region. It is possible that the pleural ganglion may 

 in most cases be represented by but a few ganglion cell's 

 the presence of which is not discernible to the unaided eye. 



May I, as I am writing about this animal, direct atten- 

 tion to an error that is universal in text-books? The 

 muscles always spoken of as retractors and protractor of 

 the foot have not the function that their titles imply. The 

 protrusion of the foot is due to vascular turgescence, and its 

 withdrawal to relief of the turgid condition and contrac- 

 tion of the intrinsic pedal muscle fibres. The muscles in 

 question move the shell, the foot being the fixed point. 

 Thus the so-called anterior and posterior retractors of the 

 foot should be styled the protractors of the shell, and the 

 protractor of the foot the retractor of the shell. I may 

 mention that I have often seen Anodonta go backwards 

 when its deliberate movements have led it into a cul-de-sac 

 in the aquarium. Oswald H. Latter. 



Charterhouse, Godalming, October 24. 



LORD KELVIN AND HIS FIRST TEACHER 



IN N.ATURAL PHILOSOPHY. 

 COME interesting early recollections were related 

 •^ by Lord Kelvin on October 17, on the occasion 

 of the unveiling of a stained glass window, by Henry 

 Holiday, in the Bute Hall of the University of Glas- 

 gow in memory of John Pringle Nichol, LL.D., 

 professor of astronomy, 1836-1859, and his son and 

 daughter, John Nicho'l, LL.D., professor of English 

 language and literature, 1862-1889, and Mrs. Jack, 

 who was born in 1837, in the University, and died 

 there in 190 1. Prof. J. P. Nichol was the author of 

 numerous valuable works, including the famous book 

 on the " Architecture of the Heavens." The account 

 which Lord Kelvin gave of his own young days at 



