MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 233 
of the median apex; in S. guadrata (fig. 12) this was found to lack side cones. 
In this species the radula has a length of 1 mm and a breadth of 0,35 mm; it 
carries about go rows of the formula 11.6.1.6.11. In S. fessel/ata the radula 
(fig. 13) measured 0,7 mm in length and 0,2 mm in breadth; its rows were 
about 60, each with 10.5.1.5.10 teeth. 
About the intestinal canal there may be mentioned the relatively great 
extension of the liver, which occupies the two apical whorls and a part of the 
third, as well as that of the stomach, the length of which is about half a whorl. 
Fig. 12. Teeth from the radula of Stephanoda guadrata Fér. X 500. 
Fig. 13. Teeth from the radula of Stephanoda tessellata Muihlfeldt. X 750. 
With respect to the shape of the kidney and the ureter it is to be observed 
that the latter is short and bent backwards as in Testacellidae (cf. LANG, 1900’, 
fig. 123 C, p. 115); thus no second ureter is present at all, a feature announcing 
a primitive stage of organization. The same arrangement was found in S. /zvata 
from Tierra del Fuego. 
Fam. Zonitidae. 
Hyalinia cellaria Miller. — Masatierra (?*/12 1916) 4 sps., max. diam. 
10,; mm. This species has not before been recorded from Juan Fernandez. 
Hyalinia alliaria Miller. — Masatierra (?°/4 1917), among leaves, a few 
sps., max. d. 6,7 mm; Aug. 1917: the Portezuelo quebrada, up to 200 m, among 
leaves and on ferns, 4 sps., max. d. 6,5; the Yunque quebrada, median portion, 
among leaves and on ferns, a few small sps. — Puerto Frances, about 400 m, 
under leaves on the soil, many sps., max. d. 6,5. — Salsipuedes Ridge, about 
350 m, on ferns and under leaves, 7 sps., max. d. 6,5. Masafuera, among ferns 
(12/3 1917), many sps., max. d. 7 mm. The species has not hitherto been recorded 
from Juan Fernandez. 
Fam. Helicidae. 
Helix aspersa Miiller. — Masatierra ('*/12 1916), numerous sps., max. h. 
29 mm. This species which has been introduced to the most separate parts 
of the world, and even to Chile (cf. TAYLOR 1910%, p. 273), has not until the 
present been recorded from Juan Fernandez. 
1 Lehrbuch d. vergl. Anatomie. 2. Aufl. Mollusca (von K. HESCHELER). 
2 Monogr. Land & Freshwater Moll. of the British Isles. Part 17. Leeds. 
