1920.] of the Mar ocean "■Middle- Atlas. ^^ 279 



exposure to uot altogetlier dissimilar climatic con- 

 ditions o£ their corresponding npper zones 



Nearly half the plants found in the higher region 

 of the Great Atlas are absent from the Andalusiau 

 Sierras, although a notable [proportion are to be found 

 in Central and Northern Spain." 



((/) '• Of special interest is the fact that many of the 

 s}jecies thus absent from S. Spain arc plants of 

 Central Euru[)e .... (the so-called "Germanic"' 

 Flora), most of which extend to the north part of 

 the Spanish Peninsula, although some of them are 

 altogether wanting in the Floras of Spain or Portugal." 



Hooker concluded that (for reasons explained in the book) 

 "it is at least possible that the wide diffusion of many species 

 constituting the so-called "Germanic"" Flora may date from 

 a pei'iod much more remote than is ordinarily supposed" 

 (Pleistocene). 



In the lioht of this conclusion Plate XI. r illustrates a 

 possible early source of influence on Distribution, through 

 the handing over, as it were, of the lliff by Europe to 

 Africa. 



Let us now review the subject in the light of (present 

 knowledge of) the distribution of Birds in Mauretania*. 



Excluding purely marine forms, the list of Sedentarj' (or 

 resident) birds of Mauretania is represented by f 93 genera 

 and 122 species composed as follows : — 



A. 8G species also found in South Spain, avIiosc further 

 range is entirely " Palasarctic " and as follows : — 



•10 are widespread to the north and north-east over the 

 " European " and/or "' Siberian "" sub-regions. 



11 spread easterly to the Far-East over the "Mediter- 

 ranean"' and " Manchurian "" sub-regions. 



* As represented by luodeni Timisia, Algeria, and Marocco. 



t All tigures that follow must be taken as approximate only. 

 Limitation of space forbids publication of the lists from which the 

 figures have been compiled. 



