PITYMYS 773 



in P. savii, the temporal ridges wide apart and barely per- 

 ceptible. Auditory bullae rather larger than usual in P. subter- 

 raneus and more smoothly inflated. As compared with that of 

 P. pyrenaicus the skull is immediately recognizable by its flat 

 dorsal profile and short, broad, excessively flattened brain-case. 

 Teeth as in Pitymys pyrenaicus. 



Measurements. — External measurements not known. For 

 cranial measurements see Table, p. 775. 



Specimen examined. — The type. 



PITYMYS GERBII Gerbe. 



1879. Arvicola (Microtus) gerbii Gerbe, Le Naturaliste, i. p. 51, July 1, 



1879. 



1880. Arvicola (Microtus) gerbei Gerbe, Bull. Soo. Zool. de France, Paris, 



v, p. 49, pi. iv, figs. 1-9. 

 1910. Pitymys gerbei Trouessarfc, Faune Mamm. d'Europe, p. 186. 



Type locality. — Dreneuf, Loire-Inferieure, France. 



Geographical distribution. — Known only from the type locality. 



Diagnosis. — In general like Pitymys savii and P. pyrenaicus, 

 but skull somewhat heavier, and interparietal lozenge-shaped, 

 narrowed at outer extremity to an acute point which usually 

 does not come in contact with temporal ; m 3 with crown 

 decidedly shorter than that of m 2 , its first outer triangle opening 

 broadly into inner triangle. 



External characters and colour. — Apparently about as in 

 P. pyrenaicus, so far as can be determined from a somewhat 

 faded mounted specimen. 



Skull. — The skull differs from that of Pitymys pyrenaicus in 

 greater relative depth and breadth throughout, shorter, heavier 

 rostrum, shorter incisive foramina, wider interorbital region, 

 and in the very peculiar form of the interparietal, as already 

 described ; nasals conspicuously angular-emarginate posteriorly ; 

 auditory bullae rather large. 



Teeth. — The teeth do not differ from those of Pitymys 

 pyrenaicus except that the third upper molar is shorter and its 

 first outer triangle opens broadly into inner triangle, a condition 

 more usual in members of the ibericus group. 



Measurements. — The following measurements are given by 

 Gerbe : head and body, 94-95 ; tail, 27-28 ; hind foot (c. u.) 17. 

 For cranial measurements see Table, p. 775. 



Specimen examined. — One from Dreneuf (paratype) in Paris Museum. 



Remarks. — This species is well characterized by the great 

 general breadth of skull, unusually wide interorbital region, and 

 very peculiar interparietal. The last character might be sup- 

 posed to be an accidental variation or abormality were it not 



