228 NILS HJ. ODHNER 
The shape of this shell may vary somewhat: in var. d/atatum the shell 
is more depressed and the umbilicus is wider but half-covered by the columellar 
margin; the last whorl at the same time is more 
ot angulated at the periphery. It measures diam. 
of 1,3, height 0,8 mm; whorls 3 3/4. 
Locality: Masatierra (Aug. 1917): Centinela 
Ridge, about 650 m above sea level, under ferns, 
3 sps. (type). — Puerto Ingles, about 400 m a. s., 
thick forest, 3 sps. (figs. 18—20), and 200 m, in 
a leaves, I sp. — Salsipuedes Ridge, about 350 m, 
WG 
I sp. — Piedra Agujeriada Valley, 3 sps., var. 
Fig. 6. Teeth from the radula of ailatatum (figs. 21-23): 
Punctum conicum un. sp. (above; X The radula (text-fis. 6) measures only o 
1460) and Endodonta involuta n. sp. ; ( eee 5 pe 
(below; X 750). mm in length and bears about go series, each 
containing 13.1.13 bicuspid teeth. The jaw has 
the characteristic structure of thin plates (about 16 in number) and is about 
O,r mm in breadth. 
Endodonta (Charofa) involuta n. sp. Pl. 9, figs. 27—29. — Shell fragile, 
planorboid, with sunk spire and broadly excavate umbilicus; whorls involuted, 
the last widest; protoconch radiately striate. Sculpture consisting of fine trans- 
verse riblets, almost perpendicular, about 22 in a millimetre, the interstices 
between them with a few (about 3—5) finer transverse striae; no spiral striation. 
Aperture narrowly meniscoid, somewhat broader sinuous below than above, with 
simple lips and without denticles. Colour white with brown radiating stripes 
which are parallel to the riblets in their upper part and more retracted than 
these in the middle and on the lower side of the shell. Dimensions: diameter 
2,4, height I,2 mm; whorls 5. 
Localities: Masatierra, Centinela Ridge, about 500 m above sea level, under 
ferns (Aug. 1917), I sp, figs. 27—29. — Puerto Ingles, about 400 m, thick forest, 
many small sps., and about 200 m, I very small sp. 
This species evidently belongs to the same group as £. d7concava Pfeiffer 
from New Zealand (cf. SUTER 1913’, p. 729), but it is smaller and has twice 
the number of riblets as well as another shape of aperture. In a small specimen 
the radula (text-fig. 6) was examined; it measured about 0,36 mm in length and 
about 0O,r2 mm in breadth. The number of rows was 50—60, each consisting 
of 8—10.1.8—1o teeth. The median tooth had a very narrow basal plate, a 
small mesocone, and a minute denticle outside it. The first lateral was the 
largest, and regular, with a strong mesocone and smaller ectocone; the 2 following 
teeth were alike, then the ectocones became longer, of about the same length 
as the mesocone; the 7th tooth had 4 cones, and the 8th had an almost entire 
margin. 
Endodonta (Charopa) masafuerae n. sp. Fig. 7. — Shell minute, very 
thin and fragile, discoidal with slightly convex spire and moderately wide um- 
' Manual of New Zealand Mollusca. Wellington, N. Z. 
