32 
VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
The statistical description given in table 9 comprises the figures for the entire 
series of “‘adult”’ shells taken in Guam, and also for the individual series from 
Barrigarda and Oco; only in the two places specified were enough snails secured to 
justify a statistical analysis. The obvious differences between the two colonies are 
manifested in the absolute width, and in the proportions both of the shell as a 
Range (class values): 
Barrigarda 
Mean value: 
Barrigarda 
Standard deviation: 
Barrigarda 
TABLE 9.—Partula fragilis, Guam. Statistical description. 
Length. 
Shell. 
Width. 
Proportions. 
Length. 
Aperture. 
Width. 
Proportions. 
Length aper- 
ture + length 
shell, propor- 
tions. 
mm. 
13.55 —15.95 
12.95 —15.35 
12.95'=15.95 
14.4000 +.1062 
14.1346+.1625 
14.4000 +.0847 
mm. 
9.30 —10.50 
8.50 —10.10 
8.50 —10.70 
9.8000 +.0863 
9.4693 +.0938 
9.7722 +.0590 
p. ct. 
64.5 —71.5 
63.5 —70.5 
63.5 —73.5 
67.8333 +.4921 
66.4231 +.3153 
67.7778 +.2684 
mm. 
7.90 —9.30 
7.30 —9.10 
7.30 —9.50 
8.3333 +.0671 
8.2077 +.0825 
8.3555 +.0496 
mm. 
6.10 —6.70 
5.70 —6.70 
5.70 —7.10 
6.3500 +.0424 
6.2077 +.0478 
6.3444 + .0356 
p. ct. 
72.5 —79.5 
73.5 —77.5 
70.5 —80.5 
76.2500 +.4363 
75.5000 +.2645 
75.9444 +.2519 
p. ct. 
55.5 —59.5 
55.5 —60.5 
55.5 —62.5 
57.6666 +.1920 
57.8846 +.2492 
57.9722 +.1644 
ef | 
>So  ———————SS.|§_@_—E=_"q{]a@{a@NaNanDnana2paRR=a2=2z[!=|=&«OO@OQDT"=EFHnR0anaEEETETETETOEDan=_EDEE==apEP!|«dO UEFEE{DaEEehaaDNNaPlT"=9]=|=$EF_|-lLDSS OO —_—SL||«-E- ——CLL—L—P@llNnaDaPB]E]|» _——LL—L——aBaBananSS||=== 
0.5454 +.0751 
-8685 +.1149 
-7533 4.0599 
0.4435 +.0610 
.5014+.0663 
5253 4.0417 
2.5276 +.3479 
1.6853 4.2229 
2.3876 +.1898 
0.3448 +.0474 
4411 +.0583 
4412 +.0351 
0.2179 +.0300 
-2556 +.0338 
-3166 +.0252 
2.2407 +.3085 
1.4142 +.1870 
2.2414+.1781 

0.9860 +.1357 
1.3324 +.1762 
1.4622 +,1162 
whole and of the aperture. The two shells from Umatac Madog are not unusual 
when compared with those of the north, saving only in the wider proportions of the 
aperture in one instance. 
TABLE 10.—Partula fragilis, Guam. Color classification. 
Color-classes of ‘‘adults.”’ 
Numb Number of 
Locality. rn of A “adolescents” 
adults. Darker Buff White (buff). 
buff. 
Northeast Region: 
“Lavage cewcdtoadeek s 2 1 1 5% 
Santa Osa. cere te 0 rhe 1 
ASAdOS Osim. sete intete 1 1 2 
East Central Region: 
Barrigardas:..6<i5 ae re 43 6 6 1 1 4 | 
Wkudthasuciuonte sshieicg 3 2 1 4 1 
Dadedow ss. teaten vee 2 2 ‘ 1 
SAUCIO bonnie eater 1 1 Ss) 
Coast Central Region 
TuMOn ss, .doe.ceue 0 he Ps ie 3 
OCO Rn he sa ort us eke 13 10 1 2 12 
Agafia, garden......... *11] x, {1] 
Southwest Region: 
Umatac Madog........ 2 2 $s ihe 1 

* “ Dead shell.” 
Originally the color of the shell is corneous buff, with close strigations of 
yellowish brown and lighter buff. Even in quite young individuals, the shining 
cortex wears away, beginning at the apex, thus leaving the whitish substratum 
exposed. Although the total range of coloration is much restricted, three color- 
