46 NORMAN: ON THE MOLLUSCA OF BERGEN FIORDS. 



Necera lamellosa, M. Sars. Chr. Videns-Selsk. Forliand, 

 1868, p. 257 (name only, no description). 



Generally distributed in suitable localities in 100 — 400 f. 

 throughout the district examined. Younger specimens of 

 this small Neczra are easily recognised by their elevated con- 

 centric lamellae, but as the shell increases in size the lamellae 

 become more and more obscure, and it then approaches very 

 near to N. obesa, Love'n. 

 loi. Ne^ra rostrata, (Speng.) 



Ne(2ra rostrata, Jeffreys. Brit. Conchol., iii., p. 51, v., 

 191, pi. xlix., fig. 4. 



Fine specimens taken in the neighbourhood of Bukken. 

 It is somewhat remarkable that the six species of Necsra 

 found by me in the neighbourhood of Bukken are the same 

 six forms which are given in the most recent list of Mediter- 

 ranean Mollusca, that by Marquess Monterosato ("Nuova 

 Revista delle ConchygHe Mediterranee, 1875), ^^ the only 

 members of the Genus inhabiting that sea; yet two of these 

 are nevertheless altogether absent from the British Seas, and the 

 remaining four extremely local and rare. The fact of their 

 absence or scarcity must be explained, I think, by the few 

 spots in the British Seas where the conditions favorable to, if 

 not necessary for, their existence, are fulfilled; namely, a 

 depth of water exceeding 50 fathoms and a bottom of very 

 fine mud. Loch Fyne is almost the only spot in our seas 

 which fulfils these conditions. Around Shetland there is 

 sufficient depth of water, but the bottom is sometimes coarse, 

 more generally a grit (broken shell and Foraminifera), but 

 very rarely, if ever, a fine mud. Indeed I do not recall to 

 mind an impalpable mud as occurring anywhere in the open 

 sea round Shetland. 

 107. Panopea plicata, (Mont.) Living specimens, south side 

 of Ivors Fiord, 200 — 300 fathoms, Station 13, 



J.C ( ii., Feb., 1879 



