Studies on the Variation, Distribution, and Evolution of the Genus Partula ...Carnegie Institution of Washington, 1916 - Partula |
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Common terms and phrases
adolescents Ahonu Aoua Aperture apex Apirimaue Atehi Average brown cent cestata characters clara coil collection colony color color-classes columella dark eggs Faarumai Fautaua Valley fecundity Figs figures filosa Garrett gravid ground-color Haavini Hamuta Haoma heredity Huahine hyalina individuals inhabited island Length aper length shell lignaria Mahaena Mangaia Maruapoo MEAN VALUE Moorea nodosa occur Oopu Orofere otaheitana affinis otaheitana amabilis otaheitana otaheitana otaheitana rubescens otaheitana sinistrorsa Papeete Papehue Papeiha Papenoo Valley Paraura parents Partula otaheitana Pease phæa Pirai Valley plate 27 Pohaitara population primary variety Proportions Punaauia Punaruu quadrant Raiatea Red adults red class red young relative numbers revolving bands sinistral and dextral snails Society Islands species specimens STANDARD DEVIATION statistical strigations Taapuna Tahaa Taharua Tahiti nui Taiarapu Tautira Tiarei tions Tipaerui tooth Total Tuauru ture types unbanded Ururoa Vaiaaia Vaihiria whole whorl Width Yellow adults yellow and red yellow young
Popular passages
Page 11 - ... with only one exception, each group of islands has its own characteristic species which occur nowhere else. "The same correlation between geographical and specific discontinuity is displayed by the species of the different islands of one and the same group for each member possesses distinct species not found in the others " (p. 11) ; and that the various varieties are confined within rather easily definable geographic limits. It would seem that the isolation factor had been so taken for granted...
Page 299 - ... neighboring localities, there must be environmental factors for the observed differences; but even this contention breaks down when individuals of a mutant group, like dextral sinistrorsa, appear in a valley along with their unchanged relatives. In a word, the role of the environment is to sot the limits to the habitable areas or to bring about the elimination of individuals whose qualities are otherwise determined, that is. by congenital factor s.
Page 299 - But it is not necessary to review the whole case at length, for in many of the foregoing pages the significance of the facts as observed has been pointed out. Brought down to the most succinct expression, the general conclusions are: "(.1) The negative statement that no differences in the environmental factors affecting the Partulae can be discovered which would account for the production of diverse but intimately related forms in two contiguous valleys, such as typical crassa and crassa occidentalis...
Page 299 - As to subvarieties, the sporadic occurrence of reversed or peculiarly banded affinis in widely separated localities could scarcely signify the operation of identical external factors in such places and not in the intervening territory; dextral sports produced in greater or less abundance in certain colonies of sinistrorsa and sinistralis surely can not arise except through the operation of congenital factors that are independent of the environment. "But it is not necessary to review the whole case...
Page 12 - The evidence tends to prove that the dominant geological process in South Pacific regions has been one of subsidence, which has progressively isolated various mountain ranges previously connected, so that they have become separate island-masses, which, in their turn, have been subsequently converted into the disconnected islands of the several groups.
Page 299 - ... environmental" influences affecting the snails. Doubtless there are few who would hold external circumstances accountable for the existence of different combinations of species in different localities, such as hyalina and otaheitana in Fautaua Valley, and hyalina, clara, nodosa, and otaheitana in Punaruu Valley. It is equally difficult to discern reasons for regarding diverse combinations of varieties as the products of one and the same environment, such as rubescens and affinis in Papenoo, rubescens,...
Page 120 - The above-mentioned valley being close to the principal harbor which was frequented by the earlier navigators, it is undoubtedly where Bruguiere's type was obtained. "The Fautaua shells, which are very variable in size, shape, and color, are never ornamented by spiral bands, and about one-third of the specimens are sinistral. The parietal tooth is nearly always present in the adults, and...
Page 185 - Slightly elongately ovate, rather solid, compressly umbilicate, dextral,1 finely, roughly, and irregularly striated longitudinally, transversely very minutely striate, sutures impressed, sometimes faintly marginated; lip narrowly thickened, occasionally connected with the columella by a thin callosity; columella dentate. Color light or dark chestnut brown, sometimes striped with darker or wholly of a straw color.
Page 297 - ... of stability for these islands in particular needs revision. Crampton's conclusion is : "The occurrence of related forms [of land snails] in Tahiti, Raiatea, and Moorea means that in former times these islands were connected by land ; that the common ancestral stock ranged over the whole land mass, and that its local products differentiated into the distinct species after the process of subsidence had isolated the mountains now forming the separate islands."1 ATo truncated volcanoes are known...
Page 301 - P. t. elongato-ovata, dextrorsa, solida, compresse umbilicata, tenuiter et irregulariter longitudinaliter striata; anfr. v., plano-convexis, sutura impressa; apertura oblongo-ovata, labro anguste rotundato; fusca vel flavicanter fusca, nigro-fusco trifasciata. "Long. 22, diam. 12 mill.