128 Proceedings of tJte Royal Society of Victoria. 



kSkL'LL. 



? 



Greatest length - - - - 26*2 



Basal length - - - - - 22-6 



Greatest breadth - - - - 14 "3 



Nasals, length - - - - - 9 "3 



Nasals, greatest bi'eadth - - - 3"0 



Interorbital breadth - - . 3-7 



Interparietal lengtli - - - - 4 1 



Interparietal breadth - - - 9*6 



Brain-case, breadth - - - - 12'8 



Anterior zygoma root - - - 3*2 



Diastema - - - - - - 6 '5 



Palate, length - - - - - 14-0 



Anterior palatina foramina - - 3*9 



Upper molars, length - - - 5*2 



Lower molai's, length - - - . 4"9 



Condyle to incisor tip - - - 17 "4 



Coronoid tip to angle - - - 8-8 



Habitat. Sj^ecimens marked A and B are fronj Porcupine 

 Sandhills, Wycliffe Creek ; C from Barrow Creek ; and D from 

 Untaiinua, Porcupine Grass, Alice Springs, Central Australia. 



Ohs. Some immature specimens from Alice Springs I 

 referi'ed to the genus Mastacomys. Having since examined 

 further material, including fossil teeth from the Wellington 

 Caves, I now consider the Central Australian specimens to be 

 vei'y young examples of ]ifus nanus. 



EXPLANATION OF PLATES. 



Fig. 1. Conilurus apicalis, Gould. Skull x H. 



,, 2. Podanomalus longicaudatus, Gould. Skull x 1^. 



„ 3. Thylacomys cervinus, Gould. Skull x 2. 



,, 4. Mus nanus, Gould. Skull x 2. 



a, skull in profile ; b., ditto from above ; f, ditto from below ; 

 y/, upper molars ; e, hind foot ; f, pouch. 



