200 Mr. K. Hall on Birds 
" rookery '' (iu wliicli I had previously wandered), arid tliey 
had taken from a portion of it about eight Imndi'ed eggs, 
leaving some two hundred^ and giving the bij'ds the oppor- 
tunity to lay again undisturbed. The measurements of 
the eggs do not vary much^ and one pattern oi marking 
governs the bulk ; in the minority there are differences. 1 
observed : — 
(a) Whitish ground, purplish spots appearing as if beneath 
the surface and purplish-red spots just above it; on the 
surface conspicuous spots and blotches of a chestnut-umber. 
(b) Ground-colour of green, which is rare, the spots being 
dispersed as in [a). 
(c) Dull rufous ground-colour, with varying spots : this 
is not so rare as (6). 
(d) Reddish-white ground-colour, which is not uncommon, 
the spots varying in size and number. 
The following types, attracting the eye at a glance, 
provided a series of specimens shewing the stages of pigment- 
influence in passing along the oviduct : — 
(1) Quite white, exceptional. Several years ago I received 
specimens of this kind from Maiden Island. 
(2) White, with an innermost faint purple layer of spots 
and blotches. Specimens varying greatly in size. 
(3) Similar to (2), but with a second and stronger layer of 
spots upon the surface. 
(4) White ground-colour, with purple and chestnut spots, 
which are quite uniform ; few blotches. 
(5) The type described as (a). 
(6) The type described as {b) . 
(7, 8, 9) The type described as {c) ; the extent of ground- 
colour, and therefore of the spots, variable, some lightly, some 
heavily marked. 
(10) Similar to (c), with few but heavy blotches. 
The second ^^ rookery,'' at the other end of Rat Island, 
seemed to contain much the same types of eggs, and remained 
untouched. This is the only one of these islands which the 
'' Sooty '' uses for breeding. Each '' rookery '' contains some 
two thousand birds. 
