new Avatrallan Murida'. 609 



of Thtoinya. Supia »il)itiil edges sqiiurt', neither roundeil 

 nor rid;;cd. Piilatal foiuniiiui long and narrow. Ineinors 

 slender, more so than in I's. tianus. Molara light and 

 delicate. 



l)init'nsi()ns of the type (measured in skin) : — 



ll.iid and body IKJ mm. ; tail 129 ;' hind foot (wet 2G) ; 

 oar (w«'t) 21. 



Skull : greatest length 30 ; zygomatic breadth 15 ; nazals 

 12; intenirbital br«'ailth 4; breadth of brain-case 13*7; 

 palatilar length liJ*3 ; palatal foramina GG ; uj)pcr molar 

 serit's 4*8. 



//(»/'. Siiaik's Hay, Western Australia. Type fuoni 

 Peron's Peninsula ; a picked-up skull from IJernier Islaii"! 

 [Shortrt'di/f). 



T,,pe. Old fi-mal.'. B.M. no. 58. 12. 27. 14. Collected by 

 Dr. F. M. Hayner during the voyage of the * Herald ' ; pre- 

 sented by the Admiralty. 



This pretty mouse has a superficial resemblance to 

 Ps. afho'-uii reus (which has a local sub.-*pocies on ISliark'.s 

 Pay — Ph. a. squaforum), but is really more nearly related to 

 the Ph. tiiiuus group. It is readily distinguishable by its 

 pale colour and long bicolor tail. 



During the Halston exploration of \V. Australia, Mr. Shoi t- 

 ridge picked up a dried skull of Ps. pra'conis on Bi-rnier 

 Islan<l, but he th<uii;ht that the animal had become extinct 

 there. The type was obtained dnriiit^ the historic voyage of 

 the 'Herald '"in 1858. 



Pseudomys [Gyomys) giaucus, sp. n. 



A large eas^tern representative of Ps. albocinertus. 



Size largest ot the suligenus. Fur soft and fine ; hairs of 

 back about 11-12 mm. in length. General colour pale blue- 

 grey, not so pale as in albocinerens ', under surface paler grey, 

 the bases of the hairs slaty, their tips greyish white. Ears 

 of medium length, greyish. Hamls and feet silvery white ; 

 last hind i^ob'-pad sniidl, lound. Tail rather longer than head 

 and body, pale brown above, white on the sitlcs and below. 



Skull in general characters quite like that of Pn. albo- 

 cimreus, but larger and more robust throughout. Anterior 

 zj-gomatic plate more projected tbrward. 



Dimensions of the type (measured on the spirit speci- 

 men) : — 



Head and body 93 mm.; tail JIl; hind foot 22*5; 

 ear 18. 



Skull : greatest length 20 j basilar length 22*5 ; zygo- 



