THE FOULA FIELD MOUSE 



729 



each of the other sub-species of fridariensis, but its angular process 

 shows no trace of the remarkable elongation characteristic oi f. grantii. 

 These appearances are borne out by the measurements, which in 

 addition reveal some small peculiarities of the present form. The 

 absolute size of the skull is about as in / grantii, the occipito-nasal 

 length, interorbital width, nasal length and width, and the length of the 

 anterior palatal foramina, are dimensions which tend to be smaller 

 relatively than in the other sub-species oi fridariensis ; while the 

 zygomatic breadth, cranial width, and post-molar length tend to increase 

 in relative value. The rostrum is relatively wider than m. /.fridariensis, 

 narrower than in/ grantii ; the masseteric plate is relatively narrower 

 than 'mf. grantii, much narrower than in tme fridariensis ; the length 

 of the tooth-row is nearly as in f. fridariensis, distinctly shorter relatively 

 than mf. grantii. 



DIMENSIONS IN MILLIMETRES:— 



VOL. II. 



3A 



