46 TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 
occupying that part of the island nearest to the metropolis of the type, and the other, 
which is frequently dentated, is distributed over the remaining portion of the island. 
The beautiful P. bilineata is confined to a single valley on the eastern coast, and P. 
planilabrum, which has its headquarters in the large Haamene valley, just to the 
southward of the home of the former species, has established a colony in the valley 
on the north side of the one occupied by P. bilineata. P. wmbilicata, which shares 
the metropolis of planilabrum, has, like that species, avoided intruding in the home 
of bilineata, but to the northward it occupies several valleys, slightly overlapping the 
northern range of P. virginea, which latter has its metropolis on the west coast, and, 
like P. wmbilicata, ranges throughout several valleys north of its headquarters. 
Borabora, the smallest island inhabited by Partula, possesses a single species of a 
peculiar type, which has spread nearly all over the island without developing a single 
local variety. 
Hybrids between P. elongata and P. teniata, and between P. Garrettii and P. 
Thalia, are so common where those species come in contact, that I am inclined to 
believe they possess a certain degree of fertility. I have also detected several hybrids 
between P. faba, var. subungulata, and P. virginea ; one between the arboreal P. 
imperforata and the terrestrial P. lugubris; two between P. lineata, var. strigosa, and 
P. teniata; about a dozen between the arboreal P. faba and the terrestrial P. radiata; 
a number between P. faba and P. fusea,and many between the latter and P. naviga- 
toria, as well as many between the latter and P. fuba. I failed to detect hybrids 
between the Tahitian species, and found none at Huaheine. 
The examination of the animals of the various species has convinced me that they 
possess no reliable external features that will aid in their determination. The colora- 
tion in all the species varies from pale cinereous, through all the intermediate shades, 
to black or dusky slate. ‘The arboreal species are generally lighter colored than the 
ground species, and have a more expanded creeping-disk. The animals of P. arguta, 
annectens, turgida and attenuata, have the ocular tentacles longer and more slender 
than the other species, and the exudation of mucus is much more copious and more 
viscid or tenacious than usual, resembling in that respect the same difference as exists 
between the typical Helices and the arboreal Nanini. 
P. OTAHEITANA, Bruguiére. 
Bulimus Otaheitanus, Bruguitre, Ency. Meth.,i, p. 347. Lamarck, Anim. sans Vert., Desh. 
ed., p. 281. Kuster, Pl. XIV, figs. 5-6. Pfeiffer, Mon. Hel., ii, p. 71, part. 
Helix perversa, ete., Chemnitz, ix, p. 108, Pl. CXII, figs. 950, 951. 
Helix Otaheitana, Dillwyn, Dese. Cat. Shells, ii, p. 935. Wood, Ind. Test., Pl. XXXIV, 
fig. 110. 
Partula Otaheitana, Ferussac, Prod., p. 66. Reeve, Conch. Syst., ii, Pl. CLXXYV, fig. 16; 
Conch. Icon., Pl. IIT, figs. 134,136. Jay, Cat. Shells, 1839, p. 57. Pfeiffer, Mon. Hel., 
iii, p. 448. Paetel, Cat. Conch., p. 104. (Helena) Hartman, Cat. Part., pp. 9, 10, with 
woodcut; Obs. Gen. Part., Bul. Mus. Com. Zool., ix, p. 184. 
