43 



MOLLUSCA COLLECTED BY 



MR. RUPERT VALLENTIN AT STANLEY HARBOUR, 



FALKLAND ISLES, 1897-99. 



By JAMES COSMO MELVILL, M.A., F.L.S., and ROBERT STANDEN, 

 Assistant Keeper, Manchester Museum. 



(Read before the Society, June 13th, 1900). 



When this collection of mollusca was kindly placed in our hands for 

 identification by Mr. A^allentin, it was intended that the whole of the 

 zoological gatherings made by him should be published collectively, 

 but it has unfortunately been impossible for him to have this good 

 intention carried out. Although there is nothing of actual novelty 

 amongst them, these mollusca are nevertheless of more than usual 

 interest, for not only has great care been exercised in the collecting 

 and preservation of them, but appended are copious notes, all the 

 more valuable as taken on the spot : these we proceed to ciuote in 

 extenso in the accompanying enumeration. 



CEPHALOPODA. 



Octopus tehuelchus d'Orb. ? — Mr. W. E. Hoyle informs us that 

 two small Cephalopods, which we handed to him for examination, are 

 probably the young of this well-known Patagonian species. 



GASTROPODA. 



PULMONATA. 



Limnaea diaphana King. — "iV large freshwater pool, about 

 three-quarters of a mile due east of Stanley Harbour, contained a 

 number of these molluscs, which were crawling about the sand)' 

 bottom in the bright sunshine " (R.V.). This appears to be the first 

 instance, hitherto recorded, of the occurrence of a freshwater species 

 in the Falkland Isles. It was described by King from specimens from 

 the Straits of Magellan. 



Siphonaria lessoni Blainv. — "Very common on rocks, hulks, 

 and beams. Invariably found on the fringe of high water mark, and 

 never elsewhere. Spawn deposited during January" (R.V.). 



OPISTHOBRANCHIA. 

 Pleurobranchus patagonicus D'Orb. — Three examples. The 

 mantle seems more effuse than in the figure given by Tryon after 

 d'Orbigny.^ Colour, a transparent white. The shell is more calcareous 

 than are those of most other species of the genus. Low water. 



I " Manual of Conchology," vol. 16. pi. 74, fig. 92, 93. 



