Rats in Western Samoa — - Marples 
175 
TABLE 2. 
Skull Measurements of Rattus exulans 
MEASUREMENT 
LOCALITY 
NUMBER 
MEAS’D 
AVERAGE 
S 
t 
t 
PREDICTED 
FOR .01P 
P 
SIGNIFICANCE 
Greatest 
Samoa 
20 
31.48 
1.53 
length 
Upolu 
6 
32.70 
0.79 
2.71 
2.878 
<.05 
Probably 
Manono 
14 
30.95 
1.48 
significant 
Condylo- 
Samoa 
21 
29.21 
1.46 
basal 
Upolu 
6 
30.47 
0.67 
2.95 
2.861 
<.01 
Significant 
length 
Manono 
15 
28.70 
1.39 
Zygomatic 
Samoa 
23 
14.9 
0.46 
breadth 
Upolu 
6 
15.3 
0.18 
3.13 
2.845 
<.01 
Significant 
Manono 
17 
14.7 
0.43 
Inter orbital 
Samoa 
30 
5.03 
0.17 
breadth 
Upolu 
6 
5.05 
0.11 
0.376 
2.787 
>.05 
None 
Manono 
24 
5.02 
0.19 
Nasal 
Samoa 
28 
11.56 
0.62 
Upolu 
6 
11.78 
0.58 
0.988 
2.787 
>.05 
None 
Manono 
22 
11.50 
0.62 
Diastema 
Samoa 
31 
8.34 
0.46 
Upolu 
6 
8.72 
0.29 
2.443 
2.75 
<.05 
Probably 
Manono 
25 
8.25 
0.45 
significant 
Breadth 
Samoa 
30 
5.32 
0.31 
rostrum 
Upolu 
6 
5.50 
0.13 
1.65 
2.787 
>.05 
None 
Manono 
24 
5.27 
0.32 
Breadth 
Samoa 
22 
13.25 
0,29 
braincase 
Upolu 
6 
13.53 
0.14 
3.289 
2.787 
<.01 
Significant 
Manono 
16 
13.15 
0.27 
Depth 
Samoa 
19 
9.28 
0.20 
braincase 
Upolu 
6 
9.28 
0.10 
0.059 
2.898 
>.05 
None 
Manono 
13 
9.28 
0.24 
Mandible 
Samoa 
31 
17.55 
0.79 
Upolu 
6 
18.27 
0.45 
2.772 
2.75 
<.01 
Significant 
Manono 
25 
17.37 
0.75 
Maxillary 
Samoa 
31 
5.32 
0.26 
toothrow 
Upolu 
6 
5.30 
0.45 
0.135 
2.787 
>.05 
None 
Manono 
25 
5.32 
0.29 
Mandibular 
Samoa 
31 
5.03 
0.17 
toothrow 
Upolu 
6 
5.13 
0.05 
1.597 
2.787 
>.05 
None 
Manono 
25 
5.01 
0.18 
Width apart 
Samoa 
17 
2.46 
0.20 
bullae 
Upolu 
6 
2.48 
0.24 
1.1038 
2.947 
>.05 
None 
Manono 
11 
2.45 
0.18 
Width be- 
Samoa 
17 
12.87 
0.45 
tween outer 
Upolu 
6 
13.18 
0.22 
2.356 
2.947 
<•05 
Probably 
edges of meati 
Manono 
11 
12.70 
0.46 
significant 
Width be- 
Samoa 
17 
10.62 
0.47 
tween inner 
Upolu 
6 
10.94 
0.30 
2.292 
2.947 
<.05 
Probably 
edges of meati 
Manono 
11 
10.45 
0.47 
significant 
Length 
Samoa 
17 
5.81 
0.23 
bulla 
Upolu 
6 
6.00 
0.18 
3.075 
2.947 
<.01 
Significant 
Manono 
11 
5.70 
0.19 
