PARTULA GIBBA, GUAM. 87 
this color-class is an integral member of the species, and that it is not so dis- 
tinguished in qualities other than those of coloration as to be accorded the status 
of a taxonomic variety. 
How greatly two neighboring associations may differ is well illustrated by 
the inner and outer Presidio series. The numbers are sufficient to afford reliable 
determinations for comparison when the probable errors are taken into account. 
The two localities are separated only by a roadway and a narrow belt of grassland, 
yet the shells are collectively quite diverse. 
TABLE 39.—Partula gibba, Guam. South Central Region (cont.). 









































Lip. Tooth. 
Series. No. 
Yellow; Brown- 
White. yellow- orange; None. Trace. | Small. 
brown. | red-brown. 
Diiacajiia nists. mitella saty..:s syonscis 6 clslele/aee oss arent 10 1 9 54 ae 10 
mntellacrisbraeck felts rosa. ss. 0.0, «ce metas 6 5 1 6 ane ts 
PAL SPL tera Ren toy 576) a ao Sa ene 16 6 10 16 are 
Fonte A: bicolor tite castes. = Ae atte 10 3 7 Fan 10 eat: 
rr fan Cees eee eee een Aer ee ee 140 59 79 2 136 4 
mo teliasrubra.cccccscs aes te eee 31 9 22 eer A 30 1 
castanea-purpurea................ 15 er 1 14 iS ae 
WESDETALTOSER cok cisodl ae bis ebisis SRK Z 2 wee mee 2 : 
WVESPEKA-CYANeR acts cig <b is «0s 6 «alee 7 7 Ms ey. 6 1 
LYS ree eve, SERMCRS fac ss chs aite deltas 205 80 109 16 199 6 Pee 
Fonte B: bicolor. ciis ve He ws 2 nie oo es 2 2 bs ti 2 re 
Wane bel bess srsrenars cers sia iticrne tons msysne score 57 5 52 : 57 be 
castanea-purpurea.............00: 7 4 arene 3 7 Sele. 
Veapera-cyanea eac%, i 5 os. Ayine siesde's.s 10 10 10 Sere C23 
TAN e589 ROR 6 CONT EM ane CRS 76 21 52 5 76 Sele 
Asan: bicelers er be eee. aR aa 5 cnt 5 Me 5 
Wn bel efor hae ae or epea AGIs as toua auenereiotatece Ht 9 18 25 2 
mitella-rubras. 3 ss 6 sek et eke eas 5 es > 5 
Vespera-CYANCA ss 75 oc « s/aickeols op VR 2 2 2 eis 
ATIVE Rye Eovrete ine’ 5 aeeaone seek se 39 14 28 satis 37 2 


The statistics of lip-color and of tooth development (table 41) record the 
unique quality of the former in marginata and the slight degrees of the latter in 
all associations. 
Apra, West Central, and Southwest Regions—The remaining primary regions 
of the islands are sparsely settled by gzbba, and indeed the Southeast Region is 
devoid of the species, judging by the single representative collection from Inarajan. 
The points of major interest are that mitella alone was found at Orote, that it 
dominates at Salifan, and that it gives place to bicolor at the extreme southwest. 
From the statistics (table 42) it appears that the bicolor shells are unusually large 
with consistency. Some color is shown by the lips of nearly all specimens, and the 
tooth is generally absent (table 43). 
From the foregoing current account and from the statistics upon which this is 
based, it is apparent that the color-classes of various kinds are not structurally dif- 
