678 Mr. O. Thomas on the Bandicools of 
differ from the mainland Bandicoot, and on comparison I find 
the difference so marked and so constant as to be worthy of 
recognition by name. In examining the skulls I have had 
for comparison the fine series of Zsoodon obesulus obtained 
by Mr. Shortridge in South-west Australia, a series numbering 
nine males and five females, and showing well the age and 
sex characters found in this difficult genus. 
The island-form I would propose to call 
Isoodon nauticus, sp. n. 
Size markedly smaller than in the continental obesulus, the 
skull of an adult male only about 55 mm. in length, as 
compared with 70 or more in obesulus. General colour com- 
paratively pale; under surface white ; hands and feet with 
grey-brown metapodials and white digits ; tail brown above, 
whitish below. 
Skull far smaller than in obesudus, smooth, and almost with- 
out cranial ridges, the sagittal crest obsolete, and even the 
two lateral thickenings of the occipital much less developed 
than usual. Nasals much shorter and narrower than in 
obesula. Bullee not far from as broad as in obesula, but pecu- 
liarly shortened, rather abruptly cut off behind. 
Teeth small throughout. The three juxtaposed incisors, 
?-i*, together about 3 mm., as compared with 4°5 and 
upwards in obesulus. Canines short. Secator and molars 
all proportionately reduced. 
Dimensions of the type (measured on the spirit-specimen 
before skinning) :— 
Head and body 242 mm.; tail (damaged, 103 mm. in 
another rather younger specimen); hind foot 50. 
Skull: greatest length 54°5 ; condylo-basal length 53; 
zygomatic breadth 253; nasals 21°7x5:2; intertemporal 
breadth 11°6 ; palatal length 31; oblique diameter of bulla 
10°3 ; dental length 98 ; front of canine to back of m* 20°5 ; 
diameter of secator 2 ; combined length of m!8 8:5. 
Hab. Franklin’s Island, Nuyts Archipelago, S. Australia. 
Type. Adult male. B.M. no. 22.4.15.6. Collected and 
presented by Prof. IF. Wood Jones. 
The main difference of this island Bandicoot from J. obesulus 
is its markedly smaller size, as compared with continental 
specimens of corresponding sex. Its bullz are also shorter, 
and it is probable, as occurs with other insular forms of the 
genus, that there is less sexual difference in size than in 
the mainland animal. 
