[anuary 19, 191 i] 



NATURE 



0^3 



met with in 150 metres, or higher up, were with 

 few exceptions taken at night. 

 .clothone iignata may be said to approximate to this 

 group so far as distribution is concerned, and this form 

 also has large, well-developed light organs. .\ closer 

 ■^"Ti.vsis of the occurrence of these forms in different lati- 

 -; would probably reveal much of interest, though this 

 ; be reserved for subsequent investigations. 

 is important to lay stress upon the fact that these 

 ng colours, remarkable light organs, and peculiar 

 telescopic eyes do not belong to the dark region in the 

 ^ where the sunlight never penetrates, but, on the con- 

 ', to a region where there are, at any rate, large 

 itities of the rays which are nearest to the blue, 

 , and ultra-violet portion of the spectrum, 

 ere has been a good deal of disputing as to whether 

 light emitted by the light organs was entirely pro- 

 by the vital energy of the organisms, or whether the 

 isiiis had the power of transforming the ultra-violet 

 of the sunlight into rays of lesser wave-length. The 

 ations I have described here cannot, of course, decide 

 ions of this kind, but they show, at any rate, that 

 light-emitting organisms live in a medium in which 

 are quantities of rays from the sunlight ; and we 

 ;nise, further, in these forms a new biological type 

 ■ganisms, a separate group with quite characteristic 

 rd conditions of existence, 

 higher we ascend towards the surface of the sea, 

 more varied become the forms and colours of the 

 nisms, and the more diversified become also, probably, 

 conditions of life. I have up to now only been able 

 CO examine a portion of the large material from the upper- 

 imost water-layers, and will merely mention a single group 

 fnm this region, namely, the larvae and young fish forms. 

 hese we have collected a very large quantity, amount- 

 to thousands. It has been impossible to determine 

 ■ them all, as this will be a long and laborious task. 

 I A table shows how, out of 3600 transparent large 

 land young fishes, 90 per cent, were secured in the appli- 

 i ances operated from the surface down to a depth of 150 

 I metres. These forms are young stages of many different 

 I kinds of fishes. 



i A very interesting and important question is the quantity 



lof animals in the different depths. This question has not 



i been much studied yet. I believe myself that the upper 



'' ': 01 the red and dark-coloured forms is particularly 



In the Norwegian Sea I found that the occurrences 



-. .. rich intermediate pelagic life corresponded to a great 



rise in the density of the sea water, and I explained this 



i thus, that the food of the animals, sinking down from the 



! upper layers, might accumulate there. The closer study 



of our material may give more information about this 



I interesting question. 



I In my preceding remarks I have given a number of 



I instances of the obser\^ations we were able to make regard- 



! ing the depth distribution of fishes when we examine 



material collected by means of parallel hauls. But it is 



obvious, too, that this material can equally well be used 



for ascertaining their horizontal or geographical distribu- 



'•"", and it is only after studying simultaneously as well 



vertical and horizontal distribution that we can 



racterise the outward conditions under which they li%'e. 



; If we look at the horizontal distribution as found by the 



Michael Sars and compare it with previous observations 



in the northern Atlantic, we shall get some idea of how 



little knowledge we possess concerning the most ordinary 



forms inhabiting the ocean between Europe and the coast 



of the United States. I will base my comparison entirely 



on Brauer's valuable summary of what was previously 



known, and on the same instances that I have employed 



when discussing the vertical distribution. 



Black fishes and red crustaceans were caught at all the 

 stations during the cruise of the Michael Sars in the 

 .Atlantic wherever we lowered our appliances to a depth 

 of 500 metres. 



Transparent young fish were captured over the whole 

 area of investigations, though in very varying quantities. 



In the open sea over the greatest depths, the Scopelidae 

 are undoubtedly the most numerous group among the 

 voung fish. We find also many extremely interesting 

 forms with stalk eyes, telescope eyes, and so on. Amongst 



NO. 2 15 1, VOL. 85] 



those with telescope eyes there are many of a perfectly 

 transparent new form, which may in all probability be 

 assigned to the genus Dysomma. They were mostly 

 caught in the uppermost 150 metres. 



When we have succeeded in determining these young 

 stages, we will be able to throw much light upon the life- 

 history of many important species of fish. The numerous 

 forms of the group Leptocephalidae will by no means be 

 the least interesting among them. The 195 individuals 

 that were found are believed to belong to no fewer than 

 twenty species, of which a good many are entirely new. 



I have previously (in Nature of October 24, 19 10) 

 published a short description of a number of these Lepto- 

 cephalidae, which we were able to prove to be the larvae 

 of the European eel. These larvae (forty-four specimens 

 in all) have this much of interest in them as compared 

 with previous finds, that they were met with right out in 

 the Atlantic Ocean, far away from the slc^s where they 

 previously had been discovered. 



Trawlings. 



To operate the big trawl at the greatest depths of the 

 North Atlantic, about 2500 or 3000 fathoms, proved a very 

 difficult task. However, two of our hauls were quite 

 successful. The first was in the Bay of Biscay, at a 

 depth of 2500 fathoms. Our catch contained a number of 

 invertebrates, including holothurians of the genus Elpidia 

 alcyondae, sponges, and ascidians, and two fishes belong- 

 ing to the genus Macrurus. 



The second haul, between the Canary Islands and the 

 Azores, at a depth of 3000 fathoms, yielded only a very 

 few living organisms. In the half-barrel of mud brought 

 up by the trawl we found thirty pumice-stones overgrown 

 with Stephanocylis and Limopsis, and there were also two 

 holothurians {Laetmogone violacea and Elpidia, sp.), 

 sertulariae, fragments of an umbellularia, an antipathes, 

 a spike of a cidaris, fragments of shell of argonauta, as 

 well as one Bulla tjmpanica of a whale, and two shark's 

 teeth, of which the first belonged to a carcharodon and 

 the second to an exyrhina. Of fishes there were one 

 Malacosteus, one Alepocephalus, one Leptocephalus, one 

 Argyropelecus, and a form not yet determined. All these 

 I believe to have been pelagic, and to have been taken 

 during the process of hauling in. Regarding one form 

 alone, there was doubt whether to class it as a bottom 

 fish or as pelagic, namely, an unquestionably new species 

 much resembling Ipnops murrayi. 



Judging from the appearance of the trawl when being 

 lowered and when being afterwards hauled in, I consider 

 this haul to have been, technically speaking, a success, 

 and I cannot explain the catch otherwise than by sup- 

 posing that at those profound depths there was an absolute 

 poverty of animal life. It remains a question whether 

 all these great ocean floors are equally barren in regard to 

 animals, and especially fishes. So far as I know, the 

 literature on the subject only records the capture of a few 

 Macruridae from the greatest ocean deeps, this being all 

 the evidence that there is to favour belief in the occur- 

 rence of larger fish there. But is it perfectly certain that 

 even those are not also pelagic ? On several occasions 

 during the cruise our tow-nets captured over the greatest 

 ocean depths pelagic specimens of .Alepocephalus, which 

 is generally brought up by the trawl. In any case, the 

 animal life there must be extremely scant}- : and this is 

 borne out by the vertical hauls with our big net below 

 1500 metres, which I have referred to when discussing 

 Cyclothone microdon. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridge. — The professor of mineralog}' has, with the 

 consent of the Vice-Chancellor, reappointed Mr. A. 

 Hutchinson to be demonstrator in mineralogy and 

 assistant curator for five years from January i. 



Dr. Hobson has been appointed chairman of the 

 moderators and examiners for the Mathematical Tripos, 

 Part ii., 191 1. 



Mr. C. E. Inglis has been appointed chairman of the 

 examiners for the Mechanical Sciences Tripos, 1911. 



