30 MR. EDWARD DEGEX OX THE 



a possibly individual abej-ration, both of these assumptions were 

 dispelled on the discovery of this peculiarity in the female also. 



An examination of the remaining five specimens preserved 

 in alcohol, as well as of the type specimen referred to (antea, 

 p. 20), and of a second female moi^e recently described * (all 

 in the Collection of the British Museum), readily confirmed its 

 specific importance, since not one of them bore the least trace of 

 the presence of this morphological feature. 



Besides the simultaneous observation of its absence in Zono- 

 saurus niadagascariensis, belonging to the neighbouring family 

 Gerrhosauridse, a more methodical search among the rich 

 material of the Biitish Museum Collections revealed the following 

 genera and species belonging to the family of Lacertidfe as being 

 devoid also of the foramen parietale : — 



Poromera fordii, Benito River, Spanish Guinea. 



lAtcerta echinata. Kribi River, Cameroon. 



Algiroides africamis. Uganda. 



Nucras delalandii. Natal. 



Latasiia hm-deggeri. Somaliland. 



,, neumanni. Arabia. 



,, degeni. Somaliland. 



,, spinalis. „ 



,, phillipsii. „ 



GastrophoUs vittata. Zanzibar. 



Holaspis guentheri. Benito R., Spanish Guinea. 



As the above list shows, cases of absence of the parietal 

 foramen occur in seveial monotypic genera, also in the specifically 

 numerous genus Latastia in no less than five species out of ten. 

 Yet it is rather remarkable to find such a character restricted to 

 two species only in a large genus such as Lacerta. 



But more remarkable, perhaps, is the fact that all the forms 

 thus deprived of the foramen belong to the African Continent, 

 aiid that in the not strictly African genera it is restiicted to 

 A f rican representatives. 



Some of the remaining genera of this family, even of purely 

 African habitat, do not contribute any specific forms which exhibit 

 this negative character. It is curious to note, moreover, that 

 among the upwards of thirty known species of the genus Eremias, 

 about twenty of which are found in Africa, no exception to the 

 presence of the parietal foramen could be found. 



The sum total of cranial characters, as shown piincipally in the 

 immature skull of the female, points to Lacerta jacksoni being 



* G. A. Bonlenger, "Ruwenzori Expedition Reports," Trans. Zool. Soc. vol, xix. 

 part iii., Dec. 1909, p. 242. 



