November i6, 1893] 



NATURE 



d5 



erosion, and as showing how similar (allowing for the differ- 

 ence in size) are the phenomena of the Himalayan and the Alpine 

 glaciers. But I think that moulins, as a rule, are not likely to 

 be very important agents in the formation of the rock-basins in 

 which lakelets and tarns are often lodged. So far as my ex- 

 perience goes, the range over which the moulin-torrents can act 

 is very restricted ; for the crevasse, which gives the opportunity 

 to the water, is generally formed very nearly at the same part of 

 the glacier. Thus after the moulin has travelled for a very short 

 distance down the glacier, a new crevasse opens out behind it 

 and cuts off the torrent. I have frequently seen four or five 

 dry shafts in advance of the working moulin. The lateral 

 range also of the moulin must be small. Hence I think that 

 the giant's-kettle (as is usually supposed) more accurately repre- 

 sents the ordinary product of a moulin. An excellent illustra- 

 tion is afforded by the well-known ' ' glacier-garden " at Lucerne. 

 I think, also, that the rock-basins, of which we speak, are more 

 commonly found in|situations where moulins would not be numer- 

 ous or large, viz. in cwms and corries. It is, however, true that in 

 certain undulating rock districts, as parts of Scandinavia and 

 the Scotch Highlands, lakelets are common. The form of 

 these, however, does not appear to bear much relation to the 

 hollow produced by a moulin. So that I doubt whether we 

 can regard a moulin as an agent of primary importance in the 

 production of an ordinary rock-basin, though it may sometimes 

 be a minor contributory. As I have more than once discussed 

 the question of the probable cause of the formation of tarns as 

 well as of large lake-basins, it is needless to repeat what has 

 appeared in print. T. G. Bonney. 



23 Denning Road, N.W., November 13. 



"The Zoological Record." 



Ix your Notes for October 26, on p. 621, you follow the 

 Editor of the Zoological Record in suggesting that, under the 

 present financial conditions, palaeontology should be removed 

 from the volume issued by the Zoological Society, and provided 

 for by the paleontologists themselves. Against such retrogres- 

 sion we desire to protest. " Everyone knows," as you say, 

 "that an incomplete record is of very little use"; and how 

 absurdly incomplete a recotd would be that took no account of 

 palaeontology ! The objectors probably spring mostly from the 

 ranks of systematic zoologists. We will deal with them on 

 their own ground. The systematic position of I.imuliis has 

 long been a vexed question, which no one can attempt to solve 

 without consulting the work of Malcolm Laurie on the fossil 

 Eurypterids. The classification of the Crinoids has troubled 

 zoologists since the days of Johannes Midler ; but neither he 

 nor anyone ever dreamed of settling it without reference to 

 paleontology. Students of recent Bryozoa will not be grateful 

 to those who keep them in ignorance of J- W. Gregory's lately 

 published work on the Bryozoa of the early Tertiary rocks. 

 And so we might go on ad infinitiivi. Another argument that 

 may affect the systematists is that if they reject all names of 

 fossil genera and species from the record, they will have no 

 means of knowing whether the new names they may wish to 

 propose have been used before or not. It is even possible that 

 some of them may unwittingly describe as new forms already 

 described by some unknown palaeontologist. It is hardly neces- 

 sary to remind the morphologists, embryologists, and zoij- 

 geographers of the help that they constantly receive from the 

 palaeontologists ; they, at least, will not wish to have the record 

 made incomplete. 



It is suggested that every branch of science should have a 

 record, and that paleontologists should undertake the compila- 

 tion of a separate one. This would as good as double the work, 

 both for recorders and students. What we have said above 

 shows that palaeontology is not a separate science. Zoologists 

 and palaeontologists ought to be the same people, and when 

 they have strength enough they are so, as the names of Cuvier, 

 Owen, and Huxley sufficiently testify. The paleontological 

 recorder would still have to work through the writings of the 

 zoologists, while even the pure neontologists would have per- 

 petually to refer to the palaeontological record. 



What is really wanted is to complete the Zoological Record, 

 not to make it incomplete — to go forward, not backward. It is 

 admitted that some of the recorders do tackle the palaeonto- 

 logical literature. Why should not all? If a group is too 

 large for one man, then give it to two, and if a second man 

 cannot be got to work on half-pay, then double the pay. 



NO. 1255, VOL. 49] 



To prevent the record becoming too big, make it merely an 

 index, and cut out the abstracts, which are rarely correct. If 

 more money is wanted, appeal to other societies which might 

 naturally be supposed interested in the work. It is unfair that 

 a single society should bear the burden of a work that is of 

 value to all, and one can hardly suppose that it would refuse 

 kindly offers of help. We believe, indeed, that the only reason 

 why some of the recorders abstain for the present from the 

 palaeontological work is because they feel that part, at least, of 

 the expense ought to be borne by the society more directly in- 

 terested. R. I. POCOCK, 



F. A. Bather, 

 B. B. Woodward. 



British Museum (Nat. Hist.), October 30. 



Recognition Marks. 



A QUESTION in natural history has occurred to me, which, 

 I think, might with advantage be discussed in your columns. 



It is usual to account for the white tail of the rabbit {Lefiis 

 cittiicttlus) by saying that it is useful as a danger signal to others 

 of the species. Wallace, in his "Darwinism," speaking of 

 rabbits, says that " the white upturned tails of those in front 

 serve as guides and signals to those more remote from, home." 



Now, there appear to me to be two objections to this theory. 

 The first is that the tail of the hare {Lepus limidns) is also white, 

 and is turned up in precisely the same manner when running ; 

 but it is obvious, from the habits of this animal, that in its 

 case it would be quite unnecessaary for such a purpose. 



And in the second place, if this were so, how could it have 

 been produced by evolution ? The object of the white tail is 

 said to be to assist other rabbits to escape, not the possessor 

 of the white tail itself. But the principle of evolution is the 

 survival of the animal fittest to preserve its own life, not of the 

 fittest to preserve the lives of others of the same species. 



G. J. Macgii.livray. 



3 Belford Park, Edinburgh, November 6. 



Mr. Macgillivray has failed to grasp the principle of 

 natural selection when he thinks that it cannot produce a 

 character useful to other animals of the same species. The 

 action of natural selection is to preserve the species, as well as 

 each individual separately ; and, consequently, every character 

 useful to the species as a whole would be preserved. This is 

 obvious when we consider such characters as nest- build- 

 ing in birds, and milk-secretion in mammals, which do not 

 benefit the individual possessors, but their offspring ; and the 

 same principle applies to every character which is mutually 

 useful to individuals of the same species, as are what I have 

 termed "recognition characters." Neither can I admit that 

 the habits of the hare render the white upturned tail "quite 

 unnecessary." The hare is a nocturnal feeder, and a mark which 

 readily distinguishes a friend from an enemy, and enables the 

 young during their short period of infancy to keep within sight 

 of the mother, must be of considerable importance. 



Alfred R. Wallace. 



Correlation of Solar and Magnetic Phenomena. 



In writing on this subject (Nature, vol. xlix. p. 30), to 

 save space I omitted to refer to one other case of 1 resumed 

 connection. But as such omission might be misunderstood, may 

 I here briefly allude to it? M. Trouvelot, on June 17, 1891, 

 observed changes going on in connection with a luminous ap- 

 pearance near the western limb of the sun, such as he had not 

 before seen. But the magnetic movement was in this case 

 insignificant (see The Observatory, vol. xiv. pp. 326-32S;. The 

 same reasoning as before may be applied. If the smaller mag- 

 netic motions do really directly depend on solar changes of so 

 marked a character, how does it happen that many greater re- 

 corded magnetic movements remain without corresponding solar 

 change having been seen ? It is a very interesting, indeed 

 critical point, but much more information is necessary to prove 

 that such close connection really exists. 



The appearance was seen by Trouvelot near the sun's limb. 

 There is a significant sentence ending a letter from the Rev. 

 Walter Sidgreaves, of Stonyhurst {The Observatory, vol. xiv. 

 page 326), as follows : — " But there are no indications of mag- 

 netic disturbance accompanying the folar eruptions seen through 

 the spectroscope. Even the brilliant display on the western 

 limb, of the loth [September 10, 1891], has left nothing that 



