HYDROGRAPHIC CORRELATIONS 209 



mentioned is the determining factor and that the species is passively caught in a layer of constant 

 density. Nevertheless the animals appear to be strongly stenohaline and are not found in waters of 

 suitable density when the salinity is less than 34-4 % . Yet there are cold waters of low salinity and 

 appropriate density at suitable depths. The upper limits of temperature-salinity tolerance are more 

 readily explainable since in passing them the animal would be led into regions above the oxygen 

 minimum where light penetrates and so into what is well known to be a totally different life zone. 



10 



Ld 

 IT 

 D 

 I- 

 < 



cr 



Ld 

 CL 



5 



Ld 



\- 



34- 



34 5 350 



SALINITY °/oo 



35-5 



Fig. 4. The distribution of Vampyroteuthis infernalis in relation to salinity, temperature and density. 



In regard to the individual records, it will be noted that the Discovery specimens from the South 

 Atlantic Central Water fall among the Pacific group, whereas the specimen from the Somali Basin 

 finds itself in water of high salinity and temperature, of a type hitherto known to be inhabited by 

 Vampyroteuthis only in the Atlantic. Evidently, within the limits of temperature-salinity tolerance, 

 the geographical region is of no importance. 



SUMMARY 



1 . Nine specimens of Vampyroteuthis infernalis Chun were captured by the Discovery Expeditions 

 between the years 1927 and 1937. 



2. The colour of the living animal is deep purple rather than jet black. This colour is due to a red 

 or purple pigment in the epidermal cells which fades after preservation. The oral face of the web is 

 black, or perhaps deep purple, not brown as previously described. The latter colour is apparently an 

 artifact of preservation. 



3. Eye diameter and anterior fin length are used to adjust the observed mantle length in cases of 

 damage, shrinkage or distortion. Subject to such correction the specimens are found to fall into size 



