196 Mr. G. S. Miller on 



Specimens examined. — One hundred and nine from tlie 

 following localities in Spain : — La Coruna, Ooruna, 2 ; 

 Pdjares, Leon, 6 ; Arrechavaleta, Vitoria, 1 ; Santo Domingo 

 de Silos, Burgos, 20 ; Jaca, Huesca, 6 ; Panticosa, Huesca, 

 25; Lerida, Lerida, 13 ; Barracas, Castellon, 12; Silla, 

 Valencia, 1; Villalba, Madrid, 2; Bejar, Salamanca, 1; 

 Seville, Seville, 6 ; Coria del Rio, Southern Spain, 2 -, near 

 Tarifa, Gibraltar, 1 ; Venta de Baul (between Guadix and 

 Baza), Granada, 1. 



Remarks. — The Iberian water-rat is well differentiated 

 from its allies by the combination of large size, buffy coloration, 

 and broad nasal bones. In two fully adult topotypes of 

 ArvicoJa miisignani the skull is much smaller, length from 

 front of nasal to back of interparietal 32 and 34 mm. as 

 compared with 37 and 40"4: mm. in the type of sapidus and 

 the large male from Barracas. While the size of Arvicola 

 amphibius is about equal to that of the Spanish animal, the 

 British form shows no tendency toward buffy coloration, and 

 the nasal bones are very narrow, their greatest combined 

 breadth noticeably less than anterior rostral breadth. 



Arvicola tenehricus, sp. n. 



Type.—M\\\i male (skin and skull). B.M. no. 6. 1. 21. 5. 

 Collected three miles east of Biarritz, Basses Pyrenees, 

 France, December 30, 1905, by J. F. Davison, Esq. Origi- 

 nal number 7. Presented by the collector. 



Characters. — Like Arvicola sapidus, but coloration dark 

 and brownish, in strong contrast with the buffy tints of the 

 Spanish animal (upperparts a dull greyish buff, so heavily 

 overlaid with black that the general effect is not far from a 

 rather light, grizzled bister on back, and a greyish wood- 

 brown on sides ; underparts slaty grey, washed with light 

 ochraceous-buff on chest and belly; feet hair-brown; tail 

 blackish above, greyish below, not distinctly bicolor). 



Measurements. — Type. Head and body 193 mm. ; tail 112; 

 bind foot 34 ; ear 17. Skull: condylo-basal length, 41*6; 

 zygomatic breadth 24 ; interorbital constriction 4*4 ; occipital 

 breadth 17"8 ; occipital depth 10'4 ; nasal 12 ; diastema 13; 

 mandible 26*8; maxillary tooth-row 10"6 ; mandibular tooth- 

 row 102. 



Specimens examined. — Eleven, from the following locali- 

 ties : vicinity of Biarritz, Basses Pyrenees, 7; I'Hospitalet, 

 Ariege, 2 ; Porte, Pyrenees Orientales, 2. 



Remarks. — The Pvrenean water-rat resembles Arvicola 



