AMPHIPODA 



195 



The vertical range of the species may be gauged from the N 70 V net results. Whilst 

 it may very occasionally be taken from depths below 500 and even 750 m. it is essenti- 

 ally an inhabitant of the upper layers, the largest numbers being found in the top 100 m. 

 This depth distribution is shown in the following table which includes all the net hauls 

 taken exactly between our standard depth intervals, but excludes odd hauls, for example 

 165-100 m., which do not cover a standard depth range. 



Table XXII 

 The depth distribution of Parathemisto gaudichaudi as shown by the N 70 V nets 



This table may conveniently be compared with the figures showing the range of 

 temperature and salinity within the area, Figs. 7 and 8, when its preference for the 

 cold surface layer will be clearly seen. 



This species is not confined to the Antarctic Zone ; on the two oceanic lines of stations 

 it was taken in the largest numbers in the sub-Antarctic Zone; at St. 9 on the line ap- 

 proaching South Georgia from the north-east in February 1926, see Appendix II 

 (these N 70 V results are not given in Fig. 87), and at St. 70 on the line between South 

 Georgia and the Falkland Islands taken in February 1927, as shown in Fig. 87. It was 

 taken by the National Antarctic (Discovery) Expedition (Walker, 1907) abundantly 

 between 54 and 63 ° S and by the British Antarctic (Terra Nova) Expedition 

 (Barnard, 1930) from 48 30' S to 66° 45' S. It has a similar range in the northern 

 hemisphere, but may be taken in small numbers in the tropics, for the Plankton 

 Expedition took a single specimen in 7 S (Vosseler, 1901). 



Little can be said regarding its seasonal distribution from the material at present 

 available, but we may note that it was not so abundant on the line taken in November 

 1926 and May 1927 as it was in December 1926, January 1927, or March 1927. 

 Barnard (1932) states that "breeding takes place in the southern spring and summer, 

 ovigerous ?? being caught in November, December and February, and on two occasions 

 $$ with embryos in October". He found that the two forms compressa and bispinosa 

 occurred together. 



A complete record of the occurrence of the species in the area is given in Appendix II. 



Hyperoche medusarum (Krog.). This species was met with at many stations round 

 South Georgia, but was never abundant; it occurred also at St. WS 69 and WS 70 in 



