230 NILS HJ. ODHNER 



Aiiiphidoxa helicophantoides Pfeiffer. — Masatierra (Aug. 191 7): the 

 Yunque quebrada, i sp,, d. 3,5. — Rabanal, in the bottom, about lOO m above 

 sea, 2 small sps., and about 300 m, 2 small sps. — Pangal, on ferns, under 

 leaves, i sp., d, 3,5. — Beneath Damajuana, thick forest, about 300 m, i sp., 

 d. 4. — Puerto Frances, about 400 m, numerous sps., d. 4,4 mm.  — Puerto 

 Ingles, about 400 m, thick forest, i small sp. — Centinela Ridge, about 350 m, 

 thick forest, 2 shs., max. d. 2,5 mm. 



Remarks on the Genus Aiuphidoxa. 



The typical forms of this genus are the two species mentioned above, 

 which are indigenous in Juan Fernandez and found there only. Their anatomy 



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Fig. 8. Teeth from the radula of Amphidoxa helicophantoides Pfeiffer. X 750. 



Fig. 9. Teeth from the radula of Amphidoxa marmorella Pfeiffer. The lower row somewhat 



aberrant. X 7S0- 



Fig. 10. Jaw of Amphidoxa marmorella. X 75. 



has been unknown, but judging from the shell characters, PiLSBRY (1894) has 

 included the genus in the fam. Endodontidae . 



Since all the material collected by the Swedish expedition was dry, except 

 one small specimen in alcohol, I could not make the organization of the animal 

 subject to a thorough examination. The radula and the jaw, however, were 

 studied, and found to be typically endodontoid, the jaw (fig. 10) being composed 

 of band-like plates (in A. marmorella about 20 — 22 in all, in A. heliophantoides 

 about 30), the teeth having squarish basal plates, and the lateral ones bearing 

 3 — 5 denticles. In both species the median tooth has an unusually small apex 

 (quite as in Endodonta involuta from Juan Fernandez described above), but this 

 is subject to some variation, like the number of teeth and their shape, too. 

 In a specimen of y^. helicophantoides the radula (fig. 8) measured 0,9 mm in length 



