tlie 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 only, but a very distinct one. 



It is well known tliat the young of Parus hritannicus and 

 its near allies differ from the adult Ijirds 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 ver^ 

 ancient origin, much more so than its British representative : 

 it seems to represent a pre-Glaeial type mIucIi 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 well 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 re[)rcsent the most primitive type of plumage still 

 to be found in the younger stages of the allied species, while 

 the Irif>h bird has gone a step further and has added the 

 cinnamon sides and flanks. 



The Lusitanian element which is so stri)ngly 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 (^Geomulacus macu/osus). 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 

 Saxifraya 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 Iri^h and 

 Algerian Titmice, is the so-called '"&iv:[.^\\)Cl•Y\-TY^:c" (Arbutus 



9 p O 



