2.28 NILS HJ. ODHNER 



The shape of this shell may vary somewhat: in var. dilataUini 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 

 (^^ angulated at the periphery. It measures diam. 

 ■0^ i.3i height 0,8 mm; whorls 3 ^/4. 



Locality: Masatierra (Aug. 191 7): Centinela 

 Ridge, about 650 m above sea level, under ferns, 

 3 sps. (type), — Puerto Ingles, about 400 m a. s., 



0r\ thick forest, 3 sps. (figs. 18 — 20), and 200 m, in 

 y leaves, i sp. — Salsipuedes Ridge, about 350 m, 

 ^^.^JMvJCfJCVJL^ , sp. - Piedra Agujeriada Valfey, 3 sps , var. 



Fig. 6. Teeth from the radula of dilatatmn (figs. 21— 23). 



Punctum conicum n. sp. (above; X The radula (text- fig. 6) measures only 0,4 



1460) and Enaoaonta involuta n. sp. . , , , 1 , . , 



(below; X 750). ^^^ '^ length and bears about 90 series, each 



containing 13.1.13 bicuspid teeth. The jaw has 

 the characteristic structure of thin plates (about 16 in number) and is about 

 0,1 mm in breadth. 



Endodonta (Charopa) involuta n. sp. PI. 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 1,3 mm; whorls 5. 



Localities: Masatierra, Centinela Ridge, about 500 rn 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 E. biconcava Pfeififer 

 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 o,ia mm in breadth. The number of rows was 50 — 60, each consisting 

 of 8 — 10. 1. 8 — 10 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) niasafuerae n. sp. Fig. 7. — Shell minute, very 

 thin and fragile, discoidalwith slightly convex spire and moderately wide um- 



' Manual of New Zealand MoUusca. Wellington, N. Z. 



