34 DISCOVERY REPORTS 



latitude, and it is upon these units of area that the plotting of distribution is based. These areas decrease 

 in size towards the south, and as the projection is not an equal area representation the actual areas of 

 the quadrangles are not strictly comparable, but may be taken as nearly so. One of the unit areas 

 comprises in latitude 55° S, approximately 1034 square miles, in latitude 60° S, 900 square miles, and 

 in latitude 65° S, 762 square miles. The number of whales marked in each area is represented by 

 symbols, a sohd circle indicating ten whales and an open circle one to nine whales. The full number of 

 whales marked is shown by these circles, but whales from which marks have been recovered are 

 additionally represented by crosses, each cross standing for one whale. 



In the neighbourhood of the Shag Rocks to the north west of South Georgia this system has not 

 been followed in the case of Fin whales. There a circle of 70 miles radius has been drawn with the 

 Shag Rocks as centre, and all the Fin whales marked within the area circumscribed have been plotted 



Fig. I. Key chart showing place names and the two areas covered by Plates V-XXII. 



together. The intense marking in this region was carried out from a hired whale catcher, and positions 

 of the marked whales are in some cases recorded in the logs in such a way that they cannot be plotted 

 so precisely as in other regions, although they do fall within the 70-mile circle. Also, it has been shown 

 (Rayner, 1940, p. 261) that Fin whales marked within 70 miles of the Shag Rocks do not thence 

 proceed directly to South Georgia, and there is thus some advantage in plotting them as a single unit, 

 separate from those found farther east. 



In the earlier paper (loc. cit.) the numbers of whales given as effectively marked were Blue 668, 

 Fin 3915, Humpback 558, but the numbers used for the present paper are slightly lower, for they 

 include only those actually recorded as hits, together with the few which, though recorded as misses 

 or ' possibles ', were subsequently recovered. The previous report included ' half the remaining 

 possible hits' in the total, but these have now been disregarded. A few whales, viz. 16 Blues, 18 Fins 

 and 4 Humpbacks, marked by the R.R.S. 'William Scoresby' in December when approaching the 

 grounds fall a little beyond the boundaries of the charts used. Also some whales have been marked on 



