76 TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 
The range of terrestris terminates at Opoa valley, on the southeast coast. At 
Faaloa, on the east coast, there exists a form which is the P. castunea, Pease, and is 
intermediate between terrestris and vittata. It is usually chestnut-colored, constantly 
toothed on the parietal wall, and the fasciation is the same as in the other varieties. It 
has not spread any to the northward of Faaloa, but occurs more sparingly in a small 
valley between Faaloa and Opoa. 
P. NAVIGATORIA, Pfeiffer. 
Bulimus navigatorius (Partula), Pfeiffer, Proc. Zool. Soce., 1849, p. 131. 
Partula navigatoria, Reeve, Conch. Icon., Pl. IV, fig. 21. Pfeiffer, Mon. Hel., iii, p. 449. 
Carpenter, Proc. Zool. Soc., 1864, p. 675. Hartman, Cat. Part., p. 7; Obs. Gen. Part., 
Bul. Mus. Com. Zool., ix, p. 184. 
Partula variabilis, Pease, Amer. Jour. Conch., 1866, p. 203; 1867, p. 81, Pl. I, figs. 12-14 ; 
Proc. Zool. Soe., 1871, p. 473. Paetel, Cat. Conch., p. 104. Schmeltz, Cat. Mus. Godeff., 
p. 207. Pfeiffer, Mon. Hel., viii, p. 201. 
This species has its headquarters in the lower portion of Vaioara valley, on the 
west coast of Raiatea, where it is very abundant, associated with P. fusca. Though 
usually found lurking beneath decaying vegetation, it is sometimes taken on the 
trunks of trees. It does not occur in the next valley to the northward, the home of 
P. Thalia, but has spread along the lowland forests south as far as Upara valley. 
Hybrids between this species and fusca and faba are very frequent. 
Mr. Pease states, in a letter received from him in 1870, that he had determined 
navigatoria to be a small variety of P. faba, and in the following year he published 
his list of Polynesian land shells, and excluded Pfeiffer’s species from the Partula. 
According to the latter author’s description, and Reeve’s figure, it is undoubtedly 
the same as Pease’s variabilis ; and, though a misnomer, must, according to the law 
of priority, take precedence over the latter species. 
The parietal tooth mentioned by Pfeiffer, but not alluded to by Reeve or Pease, is 
not constant, but exists in about two-fifths of the adults. The former author’s ‘“‘medio 
subdentato,” likewise not mentioned by the latter two writers, is simply the lower 
angle of the small labial sinus. 
In shape it varies from ovate to oblong-ovate, as the following two measurements 
will show :— 
Length 25, diam. 13 mill. 
Length 20, diam. 13 mill. 
Mr. Pease’s accurate figures represent the normal or usual form, and his figures 12 
and 13 the typical color, which is luteous or yeilowish horn-color, with longitudinal 
strigations. Uniform whitish corneous or chestnut-colored varieties occur, but are not 
common. A more abundant variety is the usual one of a chestnut-brown base and 
sutural band. 
