62 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
marmorata 
So 
* AREA ™, 
/ occupieD SS 
yA BY clara AS ™ 
INDICATED BY GARRETT \ 
Text-Fic. 5.—Chart showing the areas of Tahiti occupied by the several primary varieties of Partula clara. 
Partula clara parva var. nov.—Punaruu to Papehue Valleys. 
The shells of the four valleys which constitute the extreme northwestern portion 
of the range (namely, Punaruu, Maruapoo, Atehi, and Papehue) are characterized 
by their smaller relative size and by a nearly uniform corneous coloration. ‘They are 
markedly different in size from the examples of the next valley, Aoua, while they 
lack the distinct streaks of many shells from Aoua and succeeding valleys. No 
banded individuals were found in this region. The variety existing in these four 
valleys is distinguished as parva, and its detailed statistical analysis is given in 
table 21. 59 of the 65 shells were measurable, of which 26 belonged to the “lighter” 
and 39 to the “darker”’ class. 
The Punaruu shells are illustrated in figures 14 to 17 of plate 20, and they may 
be regarded as typical of this variety. Only 4 specimens were obtained in Maru- 
apoo Valley out of the total series of 1,112 snails of all ages, and they agree in being by 
far the smallest obtained anywhere, as shown by figure 17, plate 20, and the statistics 
of table 21. ‘This is true for their absolute dimensions, but their departures from the 
average values in proportionate measures are far less marked. In color they belong 
to the class of the “darker”’ shells. 
The Atehi examples agree more closely with those from Punaruu in size, 
although their proportionate measures are somewhat distinctive. The “lighter” 
shells approach a clear white (fig. 20, plate 20), and the “darker” specimens are more 
