1922] on Biological Studies in Madeira 573 



It is well known that the oceanic fishes of deep water have a 

 low standard of respiration, a high degree of muscular irritability, 

 and that they sustain life long after being taken out of the water. 

 The sherny heart will go on beating for many hours after every 

 other sign of life has ceased, and I have noticed the same remarkable 

 survival of movement in the heart of the Zygena Malleus, the 

 hammer-headed shark, after I had completely severed it from a 

 recently captured monster. 



The sherny which we have been considering with many associated 

 species does not come to us in rare, solitary examples, but is present 

 in perennial supply, and the impression left after contemplating our 

 .fish markets, with their abundance and variety, and noticing the 

 patient, ingenious and primitive methods employed in capture, is 

 ■that we have in these southern waters a wealth and reserve of food 

 which, in the progress of investigation, can be made to minister to 

 the needs of regions far beyond the requirements of its present 

 •application. 



It would be both profitable and intensely interesting, by sinking 

 basket traps, such as are in use in lesser depths, to the abysmal 

 region, 3000 feet below the surface, to get an idea of the stationary 

 ■conditions of life below, and thus intercept many inhabitants which 

 would escape the dredge capture ; but as these traps should remain 

 at the bottom for twelve hours there is difficulty in carrying out 

 such observations, for one must personally investigate the take as it 

 •emerges at the surface. 



But the whole subject of these super-equatorial marine food 

 resources abounds with problems both biological and economical. 



The surface plankton and the living creatures in the adjacent 

 layers of sunlit water have yet to be explored, if only as a condition 

 precedent to the estimation of deep sea values, for we have in the 

 abundance of the surface food a key to the welfare and maintenance 

 •of life in the depths. The Globigerina ooze on the surface below is 

 ample evidence of the perpetual rain of food which must be ever 

 descending from the surface. Much of such food is doubtless inter- 

 cepted and consumed in its fall, but by far the greater part either 

 reaches the bottom or is actually dissolved in sea-water as it falls, 

 becoming thus a tangible source of deep sea sustenance. Neverthe- 

 less, the robust condition in which our deep sea fish arrive at the 

 surface when captured, and the numbers in which we know them to 

 abound, suggest that we are by no means cognisant of all the 

 nutriment which is available in those dark abysses. I have recently 

 been observing the stomach of the sherny in its various stages during 

 the evisceration of the fish in the preparation for its sale in huge 

 transversely cut steaks in the public market of Funchal. The smaller 

 surface examples always show a fair quantity of food debris within 

 them, but there is a marked difference in the stomach of the full- 

 grown abysmal fishes. The stomachs of these creatures are almost 



