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Show 588 MR. E. A. SMITH ON SHELLS [Julie 2, 4. On a Collection of Shells (chiefly Land and Freshwater) from the Solomon Islands. By E D G A R A. S M I T H. [Received May 26, 1885.] (Plates X X X V I . & XXXVII.) The specimens forming this collection were obtained by Mr. H. B. Guppy, Surgeon on board H.M.S. ' Lark,' which visited the Solomon Islands in 1882 for hydrographical purposes. Special value attaches to the collection, as in every instance the particular island where each individual specimen was collected has been noted by Mr. Guppy, to whom much praise is due for his great care in this respect, and also for the admirable manner in which the shells themselves have been preserved. A large number of Helicidae have already been recorded from these islands, but in many instances the precise island has not been mentioned. It is important to know this, for as far as our present knowledge extends some species appear to be restricted to special islands, whilst others are known to exist on several. The series of Melania and Nerilina are particularly interesting, as the freshwater forms from these islands have been comparatively overlooked. The genera Ampullaria, Paludina, Limnaa, Physa, Planorbis, and Ancylus are as yet unrecorded from this group, and the only member of the family Unionidte which is known to exist there is that (TJnio guppyi) described further on in this paper. Of Neritina only six species have been noticed, namely : - 1 . N. macgillivrayi, Reeve; 2. N. porcata, Gould ; 3. N. dubia, Chemnitz ; 4. N. christovalensis, Reeve ; 5. N. adumbrata, Reeve ; and perhaps 6. N. cuprina, Recluz. Of these numbers 1, 2, 3, and 5 were also collected by Mr. Guppy, in addition to which he obtained eleven other species. These are : - 7 . N. cornea, Linne ; 8. N. subsulcata, Sowerby ; 9. N. pulligera, Linne; 10. N. petiti, Recluz; II. A". ollvacea, Le Guillou; 12. N. asperulata, Recluz ; 13. N. variegata, Lesson; 14. N. turtoni, Recluz ; 15. N. brevispina, Lamarck; 16. N. squarrosa, Recluz; 17. N. sanguisuga, Reeve. Some of these species range not only through most of the islands of the Solomon group, but have a considerably wider distribution. This wide dispersal of these freshwater Nerites may be due to the fact that their egg-capsules are calcareous and apparently able to resist salt-water. These, if attached to floating timber, might be carried considerable distances. It is less likely that the perfect live shells would be transported in this way, for according to some experiments made by Mr. Guppy, it appears that they cannot stand submersion in salt-water for any length of time. One individual (N. cornea) survived after a submersion of 12 hours, but when a dozen were placed in the water and kept there five days not one survived, although the water was changed from time to time. 1. HELICARION PLANOSPIRA, Pfeiffer. Hab. Ugi and Santa Anna (Guppy). This, the only species of Helicarion as yet recorded from the |