MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 233 



of the median apex; in S. quadrata (fig. 12) this was found to lack side cones. 

 In this species the radula has a length of i mm and a breadth of 0,35 mm; it 

 carries about 90 rows of the formula 11.6. 1.6. 11. In ^". tessellata the radula 

 (fig- ^Z) nieasured 0,7 mm in length and 0,3 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. 



'^»fta;v^t?«?^^^ 



12 



13 



Fig. 12. Teeth from the radula of Stephanoda quadrata Ft^r. X 500. 

 Fig. 13. Teeth from the radula of Stephanoda tessellata Muhlfeldt. 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. lirata 

 from Tierra del Fuego. 



Fam. Zonitidae. 



Hyalinia cellaria Muller. — Masatierra (^Vi2 1916) 4 sps., max. diam. 

 10,7 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 

 (^^/a 1917), many sps., max. d. 7 mm. The species has not hitherto been recorded 

 from Juan Fernandez. 



Fam. Helicidae. 



Helix aspersa Muller. — Masatierra ('*/i2 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 [ci. Taylor 1910^ p. 273), has not until the 

 present been recorded from Juan Fernandez. 



^ Lehrbuch d. vergl. Anatomie. 2. Aufl. Mollusca (von K. Hescheler). 

 * Monogr. Land & Freshwater Moll, of the British Isles. Part 17. Leeds. 



