588 MR. E. A. SMITH ON SHELLS [June 2, 



4. On a Collection of Shells (chiefly Land and Freshwater) 

 from the Solomon Islands. By Edgar A. Smith. 

 [EeceiTecl May 26, 1885.] 

 (Plates XXXVI. & 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. S|)ecial 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 over- 

 looked. The genera Ampullaria, Paludina, Llmnaa, Phi/sa, Planorbis, 

 and Ancylus are as yet unrecorded from this group, and the only 

 member of the family Unionidas which is known to exist there is 

 that {Unio gvppyi) described further on in this paper. 



Of Neritina only six species have been noticed, namely : — 1. N. 

 macgilUvrayi, Reeve; 2. N. yorcata, Gould ; 3. A'^. dubia, Chemnitz ; 

 4. N. ckristovalensis. Reeve : 5. N. udumbralu. Reeve ; and perhaps 

 6. iV. cvprina, Recluz. Of these numbers 1, 2, 3, and .t were also 

 collected by Mr. Gu|)py, in addition to which he obtained eleven . 

 other species. These are: — 7. N. cornea, Linne ; 8. N. subsulcafa, 

 Sowerby ; 9. N. pulligera, Linne; 10. JV. petiti, Recluz; W.N. 

 oUvacea, Le Guillou ; 12. N. asperulata, Recluz ; 13. A'^. varieguta. 

 Lesson; 14. A'^. ^wr/on?, Recluz ; 15. A'^. brevispina, Lamarck; 16. 

 A^. squarrosa, Recluz; 17. A^. 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. corned) 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 PLANOSPiftA, PfeiiTcr. 



Hab. Ugi and Santa Anna {Guppy). 



This, the only species of HelicarioJi as yet recorded from the 



