the Irish Coal-Titmouse. 
551 
to accord full specific rank to P. hibernicus, but the ex¬ 
amination of the large series before me seems to indicate 
that the two forms to some extent intergrade, and, for this 
reason, it may now be best to regard the Irish bird as a 
subspecies onty, but a very distinct one. 
It is well known that the young of Parus britannicus and 
its near allies differ from the adult birds in having the sides 
of the head, as well as the breast and belly, washed with 
yellow. The persistency of this juvenile character in the 
adult of P. hibernicus seems to indicate that it is of very 
ancient origin, much more so than its British representative: 
it seems to represent a pre-Glacial type which has survived 
in the western and southern parts of Ireland. 
Parus ledoucii Malh., a species of Coal-Titmouse peculiar to 
Algeria, is, in many respects, the form most closely allied to 
the Irish bird. It has the sides of the head and nuchal spot, 
as w r ell as the breast and belly, strongly washed with mustard- 
yellow; but the sides of the body and flanks are greyish instead 
of cinnamon, as in the young of the British Coal-Titmouse 
and allied forms in first plumage. The Algerian bird thus 
seems to represent the most primitive type of plumage still 
to be found in the younger stages of the allied species, while 
the Irish bird has gone a step further and has added the 
cinnamon sides and flanks. 
The Lusitanian element which is so strongly represented 
in the west and south-west of Ireland is less noticeable 
in the Fauna, but is especially remarkable in the Flora. 
In the Fauna, an instance of this is to be found in the Kerry 
Slug (Geomalacus maculosus'). It was first discovered in 
Kerry, afterwards met with in Cork, and has since been 
found in Portugal, where other members of this peculiar 
genus also occur. It has not been met with in any other 
part of the British Islands. In the Flora there are 
many Lusitanian species such as Erica mediterranea and 
Saxifraga geum , the distribution of which within the British 
Isles is confined to the west of Ireland, The most interesting 
of all, however, as bearing on the question of the Irish and 
Algerian Titmice, is theso-called “ Strawberry-Tree ’’(Arbutus 
2 r 2 
