88 
The Irish Naturalist* 
April, 
A SIMPI^E METHOD OF REPRESENTING 
GEOGRAPHICAL DISTRIBUTION. 
BY R. LI.OYD PRAKGER. 
Whkn one is studying or comparing the distribution of 
animals or plants in small countries, such as this island, a list 
of the areas in which a species occurs, such as is given in 
Cybele Hibe77iica or hish Topographical Bota?iy, is not adequate. 
While the numbers or names convey a general idea to the 
mind, they leave no definite pictorial impression, and for 
actual comparison of two distributions we must have recourse 
to a map, on which we mark the areas in which each .species 
is found. 
Similarly, when we come to publish a paper dealing with 
such problems, the pictorial representation of distribution is 
very desirable for the sake of clearness, but the trouble and 
expense of preparing drawings and then process-blocks are 
practical considerations not to be overlooked. To take an 
actual example : the small map below is one of a set prepared 
Fig I. — Distribution of Cicitfa virosa (1902). 
in illustration of a recent paper by myself, in which the 
distribution of plants in Ireland is considered. The drawing 
of this set of maps involved some 30 or 40 hours of work, 
and the preparation of process-blocks from these cost the 
publishing body some i^io. Had the maps been redrawn by 
a draughtsman, as is usually done in such cases, this £\o 
would have been nearer £2^. And this expense, be it noted, 
