. 
MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 229 
bilicus (equalling about the third of the shell diameter); suture deep, whorls 
narrow. Sculpture: protoconch (17/2 apical whorl) distinctly spirally striate, 
the following whorls very closely constulate (about 
50—60 costae in one millimetre), interstices with 
one or a few fine longitudinal ribs and with obso- 
Jete microscopical spiral striae. Aperture lunate, 
without armature, lip thin. Colour of the thin cuti- 
cula horn-brown. Diameter 1 mm; whorls 31?/2. 
One somewhat fragmentary specimen of this 
shell was obtained in earth ona specimen of Exphrasia 
in Masafuera, about 1100m above the sea,and another, 
entire sp., d. 1,5; mm, whorls 3 */4, in earth from the Sanchez Plateau, 5315 m, thick 
forest (C. SKOTTSBERG, 7°/2 1917). The species has a sculpture similar to that 
of £. (Charopa) prestonit Sykes, from N. Zealand (cf. SUTER, 1913, Man. N. Zea- 
land Moll., p. 727), but the costellae are much denser. 

Fig. 7. LEndodonta (Charopa) 
masajueraé n. Sp. XK §0. 
Endodonta (7haumatodon) occulta n. sp. Pl. 9, figs. 30—32. — Shell 
discoidal, with flattened, only slightly convex spire, and a broad perspective 
umbilicus; whorls 47/4, convex and rounded, with impressed suture. Colour 
chocolate with a few irregular grayish stripes. Sculpture: first 1*/2 apical 
whorls quite smooth, the following ones with distinct and regular radial riblets, 
about 20 in a millimetre; interstices with fine radiating lines. Aperture semi-lunate, 
slightly oblique (upper lip somewhat more produced), lips simple; interior of 
aperture with one strong parietal plica and in the outer wall a basal tooth as 
well as an upper palatal tooth, both combined with a low vertical list; all teeth 
deep down in the aperture and a little difficult to observe. Dimensions: diam. 2, 
d. of last whorl 0,6, of umbilicus 0,3 mm; height 0,8, h. of aperture 0,; mm. 
Localities: Masatierra: The Yunque quebrada, the lower part, I sp., figs. 30— 
32. — Puerto Ingles, about 300 m, thin forest, 3 fragmentary shells (Aug. 1917). 
The shells were all empty, thus the radula could not be examined. 
The peculiar dentition of the aperture shows some reference to the section 
Thaumatodon which is chiefly Polynesian in its distribution. However, all these 
species have their apertures multidenticulate. A number of three teeth with a 
similar position as in the present species exists only in a few forms: £. phz/ippz- 
nensts Semper from the Philippines, Z. saw Pfeiffer from Auckland, New Zea- 
land, though the sculpture of the last-named is unlike that of £. occulta. 
Amphidoxa marmorella Pfeiffer. — Masatierra (?°/s 1917), I sp., d. 2,8 mm, 
in leaves; Aug. 1917: Rabanal, in the bottom, about 100 m above sea, some 
sps., d. 3; down in the quebrada, under leaves, 2 shs., d. 4, and about 300 m, 
numerous sps., d. 3,2. — Piedra Agujeriada Valley, many sps., d. 3,2. — Pangal, 
on ferns and under leaves, 1 sh., d. 3. — The Portezuelo quebrada, about 300m 
above sea, on ferns, 2 small sps., and 200 m, among leaves and on ferns, 5 sps., 
d. 3. — Centinela Ridge, about 500 m, under ferns, numerous sps., d. 3.3. — 
Salsipuedes Ridge, about 350 m above sea, 5 sps., d. 3,4. — Beneath Damajuana, 
thick forest, about 300 m, some small sps. — Puerto Ingles, about 400 m, thick 
- forest, a few small sps. 
