mentions the use of natural luminous bait 
by fishermen, and describes the flashes of 
coloured light emitted by different species 
of deep-sea angler fish (Ceratioidea). Thus 
it would seem that a low intensity source of 
light (perhaps greenish or bluish)°? is 
indicated, and that tare vene operation 
might be beneficial. JERLOV'S™' demonstra- 
tion of the transparency of deep oceanic 
waters means that even a faint light would 
be visible from a considerable distance. 
It is proposed to try both fish muscle 
inoculated with luminous bacteria (Photo- 
bacterium fischeri) and plastic phosphors 
for this purpose. 
Triggering Mechanism 
The trap may be designed to close on 
contact with the aes by means of a simple 
mechanical linkagel!? to spring-loaded lucite 
doors. This tripping mechanism could be 
made quite delicate if a soluble plug or 
magnesium link?» 4° were arranged to act as 
a 'safety catch!’ during descent. The lucite 
doors should have opaque covers to protect 
the catch against the possible adverse 
effects of sunlight. 
Laying and Recovery 
Suspension of, the apparatus by means 
of a wire or nylon! cable attached to a 
vessel (or buoy ) at the surface suffers 
from many obvious disadvantages, although 
it has some merit for initial trials. 
It is preferable that the device should 
descend freely and rise automatically. For 
sampling the fauna within, say, 1000 feet 
of the bottom, it is a simple matter to 
weigh down the buoyant trap with a sinker 
attached to an appropriate length of cable. 
Sampling the mid-water life is more diffi- 
cult, but it is hoped that the addition of 
a cluster of sealed aluminum tubes to the 
bathypage will enable it to become neutrally 
buoyant at a predetermined depth in the 
manner of the Swallow floatl8, 
In either of the above methods, corro- 
sion of a magnesium link9>4° or the opera- 
tion of a clockwork mechanism®, would 
release the trap after a known time. A 
241 
radar reflector and flashing light would 
facilitate recovery. 
An alternative method might be considered 
when the bathypage is to be used off an ocea- 
nic island such as Bermuda. Where deep water 
is available within a few miles of shore, and 
a fairly continuous watch could be maintained, 
closing of the trap could be arranged to 
operate the weight release mechanism. 
Conclusions 
It is believed that there is a need for 
alternative apparatus complementing the deep- 
sea trawl in the investigation of the bathy- 
pelagic fauna. This should be free of the 
disadvantages of the net, and enable the 
collection of living, undamaged specimens for 
laboratory study. Such an apparatus appears 
technically feasible. 
REFERENCES 
1. Thomson, C. Wyville, "The Voyage of the 
'Challenger!. The Atlantic." Harper 
Brothers, New York, 1878, Vol. 1, pp. 
68-70. 
2. Agassiz, A., "Three Cruises of the 'Blake'". 
Sampson Low, London, 1888. Vol. 1, p. 26. 
33) Murray, J24 and Hjort, J.., “The Depths of 
the Ocean." Macmillan, London, 1912, 
pp. 36-51. 
. Kemp, S. and Hardy, A. C., 'Discovery! 
Investigations. Objects, Equipment, and 
Methods. 'Discovery' Reports, 1929, 
A hut 
5. Kullenberg, B., The Technique of Trawling, 
in Bruun, A. et al., "The Galathea Deep 
Sea Expedition, 1950-1952". Allen and 
Unwin, London, 1956, pp. 112-118. 
6. Isaacs, J. D., and Kidd, L. W., University 
of California, Scripps Institution of 
Oceanography., Oceanographic Equipment 
Report, 1953, No. 1, S.10. 
7. Sverdrup, H. U., Johnson, M. W., and 
Fleming, R. H. "The Oceans. Their 
Physics, Chemistry and General Biology". 
Prentice-Hall, N. J., 1942, pp. 376-385. 
