June 8, 191 1] 



NATURE 



48. 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



A House divided against itself. 



Mo.si of your readers have doubtless heard of a question 

 relating to the site of the Natural History Museum at 

 South Kensington, and to a site for a new Science 

 Museum. For the latter it is proposed to utilise the waste 

 land behind the Natural History Museum, together with 

 a portion of the site assigned to the Natural History 

 Museum. The supporters of this scheme state that there 

 is plenty of land for both museums, and have presented a 

 memorial to the Government to this effect. Biologists 

 learnt of this memorial largely owing to a Question and 

 Answer in the House of Commons. They considered that 

 such a proposal seriously irnperils the future of the Natural 

 History Museum. A S99and equally influentially signed 

 memorial expressing these views is sent to the Prime 

 Minister. 



1 he spectacle is an edifying one. The scientific men of 

 ihc country are roughly divided into two camps opposed 

 to one another, while, as Sir Norman Lockyer says in a 

 letter to The Times, May 30, " there should be no conten- 

 tion between these persons — their aims are the same ; thev 

 desire to afford the best facilities for the increase and 

 coordination of knowledge in all its branches." Is there 

 no machinery which can make such contention only possible 

 as a last resort? The records of the Royal Society and 

 the British Association afford a hundred instances of the 

 cooperation of all sections of scientific men, while the 

 search for instances of the pitting of the difTerent sciences 

 against one another is almost vain. In questions which 

 affect several sciences, surely it is possible for representa- 

 tives to come together privately and discuss them freely. 

 Probably in 90 per cent, of the cases an agreement would 

 be reached, and both sides would cooperate for the good 

 of science as a whole. For the due progress of human 

 knowledge the cooperation of the different sections of 

 science is more needed to-day than it has ever been in 

 the past. All branches are becoming more and more woven 

 together, and public contention between sections can only 

 weaken the influence of science as a whole. 



J. Stanley Gardinhr. 

 Cambridge, May 31. 



Fishes and Medusae of the Intermediate Depths. A 

 note on the work of the Michael Sars. 



Dr. lijoki's account of the work of the Michael Sars 

 during last summer's cruise' is of the very greatest import- 

 ance to the marine geographer : it is the most illuminating 

 article of its kind which has appeared within recent vears. 



.^mong the many interesting questions which are raised, 

 1 wish to direct attention here to one only, which is of 

 ])anirular interest to me because of my studies on the 

 Medusae of the intermediate waters, or the mesoplankton, 

 if that term be preferred. This is the observations on the 

 vertical range of the "black fishes," "shining silvery 

 fishes," and " red prawns " of the intermediate depths. 



Briefly staTed, the result of Dr. Hjort's observations is 

 that the adult black fishes and red prawns form an 

 important community, the upper limit of which everywhere 

 corresponds with the same intensity of light, i.e. practically 

 with the lower limit to which sunlight penetrates with 

 sirength demonstrable by the photographic plate. This 

 limit is deeper in low latitudes, near<^r the surface in high, 

 that is, about 500 metres between Newfoundland and 

 Ireland ; 700-800 metres at 33° N. ; and when black fishes 

 were taken from lesser depths, such captures were made 

 at night. 



T-he silvery fishes dwell at a higher level, where the light 

 of the violet end of the spectrum penetrates with con- 

 siderable strength. 



These generalisations rest on such a mass of observation. 

 and the methods of investigation were so well chosen, that 



' T/ii; Geografhic/il Journal, vol. xxxviii., pp. 349-377, 500-513, and 

 Natcre, January 19, 191 1. 



NO. 2 1 71, VOL. 86] 



they seem to me altogether deserving of acceptance ; indeed, 

 they form one of the most important of recent additions to 

 our knowledge of oceanic biology. 



Now, among the " intermediate " or " mesoplanktonic " 

 Medusae there are two similar colour groups, one unpig- 

 niented, or faintly pigmented, but often highly iridescent, 

 as, for example, Colohonema sericeum, Khopalonema 

 funerarium, Halicreas papillosum ; the second, charac- 

 terised by very dense entodermic pigmentation, of a deep 

 red, reddish-brown, or chocolate colour. Conspicuous 

 genera among the latter are Atolla, Periphvlla, Crossota, 

 and /Eginura. 



Dr. Hjort's paper raises the question. Do the inter- 

 mediate Medusae, like the intermediate fishes, fall into two 

 classes in their vertical distribution as well as in colour, 

 and, if so, do the depth limits of the two correspond with 

 those of the fishes and crustaceans? 



Unfortunately, our knowledge of the bathymetric range 

 of all the Medusas in question is still extremely scanty. 

 We know that they do not normally come to the surface 

 except in very high latitudes, as, for example, Periphylla 

 from the surface off Cape Adare in December, 1899, and 

 Januarv, 1900, the ice then being broken up, and in 

 McMurcio Sound. On the other hand, the evidence which 

 I have collated ' shows that they are by no means 

 exclusively abyssal. During the Albatross Eastern Pacific 

 Expedition they were taken abundantly between 300 

 fathoms and the surface, and I have recently received an 

 extensive collection from the north-western Pacific from the 

 same depth zone. 



Closing-net records are too few in number to be con- 

 clusive, but it is at least suggestive that in the eastern 

 Pacific the Albatross took three genera of red Medusae in 

 a Tanner-net haul at 400 fathoms, one of which was also 

 taken in the open net from 300 fathoms, but none of the 

 transparent group, while at the same station two genera 

 of the iridescent-transparent group were taken in a Tanner- 

 net haul at 300 fathoms, and three specimens of a third 

 transparent form, Halicreas papillosum, and one of a 

 fourth, Homoconema alba, were taken in the open-net 

 haul from 300 fathoms to the surface. 



These records certainly suggest that at this locality the 

 red forms occurred, as a whole, below the transparent- 

 iridescent ones, but that the two groups overlapped at, 

 say, 250-300 fathoms. 



In my discussion of the bathymetric range of the eastern 

 Pacific Medusa?, I concluded that the upper limit of the 

 intermediate forms probably corresponded, roughly at 

 least, with the depth to which sunlight penetrates with 

 appreciable strength. But the facts with regard to fishes 

 brought out by Dr. Hjort suggests that my generalisation 

 may not hold for the intermediate Medus.x as a whole, but 

 onlv for the " red " genera. 



This question can be settled only by further records ; 

 such, we hope, will be afforded by the Michael Sats 

 Medusa? when they are worked up. But I direct atten- 

 tion to it here because, if it proves that red prawns, red 

 or brown Medusa', and black fish form a rather definite 

 faunal group dwelling below the limits of light, as now 

 seems likelv. to which, too, the pelagic holothurian Pelago- 

 thuria probably belongs, the similarly excessive develop- 

 ment of pigment in such divergent groups, in an environ- 

 ment of practical darkness, is a phenomena of great 

 interest. 



Such cases as this only emphasise the gaps in our know- 

 ledge of the life of the deep seas, and how rich a harvest 

 of discovery still awaits the student who will explore the 

 intermediate waters with a well-matured plan of operations. 



Hksrv B. Bigki.ow, 



Museum of Comparative Zoology, Cambridge, 

 Mass. 



Musical Sand. 

 Working with sand obtained from the beach at Bar- 

 mouth, North Wales, I have been able to confirm most of 

 the conclusions arrived at by Mr. Carus Wilson (Nature, 

 vol. xliv., p. 322) and by Mr. Skinner (Nature, vol. 



' Report* on the scientific r»5iil»«of iheexnert'tinn (o the Fnstern Tropica! 

 Pacific, ill chnrje of .Alexander Agassir, by the U.S.K.C. ste.Tmer Allalross, 

 . . . . XVI. The Medufse, by Henry B. Bigelow. M»-ni..it.. MustumComp. 

 Zoology, vol. xxxvii. 



