MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 23 1 



and 0,3 mm in breadth, it contained 80 rows, each consisting of a median tooth, 

 5 lateral and 12 marginal teeth on each side, the laterals having subequal endo- 

 and ectocones, the inner marginals with simple ectocones, the outer ones with 

 bicuspid or tripartite ectocones. In A. marmorella the radula (fig. 9) measured 

 about 0,7 mm in length and about 0,2 mm in breadth; its rows were about 75, 

 and in each row there were in one specimen i median + 6 lateral + 8 marginal 

 teeth on each side, all of the same shape as in A. helicophantoides ; in another 

 specimen there were 1 + 5+13 teeth in half a row, the marginals of a different 

 shape (one, tooth 14, even geminous); the median tooth in this second sj5ecimen 

 was considerably smaller. 



From the specimen preserved in alcohol it could be stated, that the foot 

 is furnished with two lateral grooves as well as a caudal mucous pore; thus 

 the reference of the genus to the fam. Endodontidae, which PiLSBRY maintains, 

 is verified. 



Stephaiioda quadrata F^russac. PI. 9, figs. 33 — 35. — Masatierra (Aug. 

 1917): the Yunque quebrada, lower part, a fe\v sps., d. 4. — Beneath Damajuana, 

 about 300 m, 4 sps., d. 6. — Piedra Agujeriada Valley, 4 sps., d. 6. — Salsi- 

 puedes Ridge, on ferns and beneath leaves, about 350 m, many sps., d. 5,3. — 

 Masatierra (No. 605), 2 sps., d. 3,5 mm. 



This species varies somewhat in painting as well as in shape, inasmuch 

 as its aperture may be more or less depressed, and generally it is more so 

 than represented on Reeve's fig. (Conch. Icon. 7, fig. 619). Also E. A. Smith 

 (1884, Proc. Zool. Soc. London, p. 279) finds some difference between the 

 »Challenger» specimens and those in Cuming's collection. I give some figures 

 of the present species on plate 9. 



Stephanoda tessellata Miihlfeldt. — Masafuera, among ferns, 2 sps., d. 

 3,4 mm (*^/3 191 7). This species was not found by the Swedish expedition in 

 Masatierra from where it is known before (Juan Fernandez; cf. Tryon, Man. 

 of Conch. Ill, 1887). 



Remarks on the Genus Stephanoda. 



The Juan Fernandez species of this genus have not been studied with 

 respect to their anatomy, but their shell characteristics evidently announce their 

 reference to the S. American genus Stephanoda. None of the typical forms has 

 been examined for inner anatomy. To the same genus, however, a small shell 

 from Kerguelen Island, S. (Aniphidoxa) hookeri Reeve, has been referred, the 

 anatomy of which has been described by SCHAKO & Pfeffer (1877; cf. PlLSBRY 

 1894). This is, however, so essentially different from that of the typical and 

 Juan Fernandez forms, that the species named must be kept apart from the true 

 Stephanodas. 



As to the external appearance of S. qtiadrata it may be stated that the 

 foot carries on each side two longitudinal furrows extending throughout its 

 length, as well as a mucous pore in the posterior end; the foot sole is undivided 

 longitudinally, showing transverse wrinkling only, no longitudinal furrows as is 



