ON LTZARDS OF THE GEXIS I'll ILOCUOllTUS. 145 



8. Oil the Lizards oE the Genus Philochortus Matschie. 

 Bj CI. A. BouLENGER, F.R.S., F.Z.S.* 



[Heeeivea J;iiiu;iry 27, 1917 : Reml Fclinuuy 20, 1917.] 



(Plates I. & Il.t) 



Index. 

 Systematic : Page 



Philocliovtus Matschie, definition and description 



of the species 145 



Fh. iiitermedius, sp. n., Somaliland 152 



Philochortus. 



Latastia, part., Bouleng, Cat. Liz. iii. p. 54 (1887). 



Philochortus Matschie, Sitzb. Ges. nat. Fr. Berl. 1893, p. 30. 



Head-shields normal, save for the occasional absence of the 

 interparietal. Nostril j)ierced between two nasals and bordered 

 by the first upper labial or narrowly separated from that shield. 

 Lower eyelid scaly, more or less transparent in the middle. 

 Collar well marked. Back with two to six longitudinal series 

 of large plate-like scales ; ventral plates feebly imbricate, with 

 ti'uncate posterior border, smooth. Digits more or less com- 

 pressed, with smooth or keeled lamellar scales inferior!}'. 

 Femoral poi'es. Tail long, cylindrical. 



Southern Arabia, Eritrea, Abyssinia, Somaliland. 



This genus differs from Lacerta and Latastia in the longi- 

 tudinal series of enlarged plate-like scales on the back, an 

 approximation to the condition in Poromera, Tachydromus, and 

 llolaspis. 



In all the species the parietal foramen is absent, and a few 

 small teeth are usually present on the pterygoids. 



The subdigital lamell?e vary according to individuals ; they are 

 usually smooth or with two series of obtuse tubercles ; sometimes, 

 however, the tubercles form obtuse keels, and in a female of 

 P. neumanni there is a ratlier sharp keel along the middle. 

 8teindachner has alread}^ observed that of the two types of 

 P. hardeggeri one has the subdigital lamellae distinctly keeled, 

 whilst in the other the keels are scarcely indicated. 



The species grouped under this genus thus afford another argu- 

 ment against the unnatural division of the Lacertidag into two 

 main groups, Liodactyli and Pristidactyli, according to the absence 

 or presence of keels on the lower surface of the digits, which the 

 state of things in Psammodromtis and Scaptira had already led 

 me to abandon. 



* Published by permission of the Trustees of the British Museum. 

 t For explanation of the Plates see p. 157. 



