MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 247 



body-whorl (equalling about half the breadth of aperture); the lower half of the 

 body-whorl is covered with a thick columellar callus. Besides fine and close 

 growth lines no sculpture was to be observed except, here and there, traces of 

 spiral impressions. This species which is closely allied to the preceding one, 

 was found in a subfossil state only: in sand at El Puente, 50 m above sea, 

 *V4i and in Aug. 1917, many shs., max, 1. 11,4, br. 9,7, another sh. 1. 12, br. 8,9, 

 thus announcing considerable formal variation. — Santa Clara, dead on the 

 sand, Aug. 1917, 3 shs., max. h. 11,3, br. 9,3, these shells being thinner than 

 the preceding ones. 



Omalonyx gayana d'Orbigny. — Masatierra ^Vi2 1916, 4 sps., max. 1. 21 

 (sh. 9,3), and V12 1916, many sps., max, 1. 19 (sh. 8,4); ^/i 1917, 300 m above 

 sea, on ferns, 4 sps., 1. 15; shaken down from bushes, 500 m above sea, V* 

 1917, many small sps., max. 1. 10,5. — Rabanal, about 300 m, among leaves, 

 many sps., max. 1. 19 (sh. 13). — Centinela Ridge, about 500 m, under ferns, 

 I sh. + some sps., max. 1. 8,5 (sh.). — Below Damajuana, about 300 m, under 

 leaves, 2 shs., max. 1. 10, and about 300 m, thick forest, 2 shs., max. 1. 6,4. — 

 Puerto Ingles, about 200 m, among leaves, i sh,, 1. 5 mm. 



The species, which was described by d'Orbigny (Voy. dans I'Amer. mer. 

 1835 — 43) from Juan Fernandez, is also recorded from the same locality by 

 E. A. Smith, in 1884. 



From an earlier visit to Juan Fernandez (Masatierra), in August 1908, prof. 

 Skottsberg brought back some small specimens of Omalonyx gayana and 

 Limax arborum preserved in the Swedish Riksmuseum. 



2. Mollusca from Easter Island. 



During their expedition to Juan Fernandez Islands, 1916 — 17, Prof. SKOTTS- 

 BERG and his zoologist K. Backstrom, also paid a visit to Easter Island, from 

 where a small collettion of shells was brought back. Every contribution to the 

 mollusc fauna of this Island is of interest, since this point, the easternmost 

 boundary of the Indo-Pacific Region, is very incompletely known in malacological 

 respect. Except a brief account of the Easter Island mollusca collected by the 

 » Albatross Expedition* published by Dall (1908^) and containing 28 marine 

 and two terrestrial forms, no list of specimens from this locality has been given. 

 The marine species now recorded all have a wide distribution within the Central 

 Pacific, thus giving evidence to the fact that Easter Island, though so remote 

 from the centre of that region, possesses a fauna of true Pacific nature. Two 

 of the five species of terrestrial mollusca taken by the Swedish expedition have, 

 on the contrary, been impossible to refer to any known species, thus being 

 described as new, a circumstance showing, as a consequence of the isolation, 

 an endemic character of the land mollusc fauna of the island, though other- 

 wise its constituents are related to Pacific forms. Two of the remaining land 



' The Mollusca and the Brachiopoda. Rep. Sci. Res. »Albatross». XIV. Bull. Mus. Comp. 

 Zool. Harward Coll. 



