NATURAL HISTORY SOCIETY OF GLASGOW. 61 



Mr John Young exhibited specimens of several species of Polyzoa 

 recently obtained from an exceedingly interesting Arctic shell-bed 

 at present exposed in the cutting of a new dock at Cartsdyke, near 

 Greenock. One Polyzoon he referred to the genus Idmonea, 

 which, he said, had not been recorded from any of the other 

 Arctic shell-beds in the West of Scotland. Mr Young stated, 

 that from the disturbed condition of the larger shells observed in 

 the deposit, and from other circumstances, considerable diversity 

 of opinion existed as to whether the bed lay in its natural position, 

 or had at some former period been dug out of some Arctic shell 

 bed cropping out on the Greenock coast, and had been brought 

 to the spot where it is now found to fill up a hollow in the 

 boulder-clay. The shell-bed, as seen in the cutting, appears to 

 be of a very limited extent ; but Mr Young would not express 

 any decided opinion as to how the disturbed condition of the 

 shells had been produced (while there was the probability of their 

 having been placed in their present position by man's agency) 

 further than by stating that it could not be by water or ice, as 

 the beautiful manner in which the Polyzoa, Serpulce, Sjnrohis, etc., 

 are preserved upon the larger shells and on the stones and 

 boulders in the deposit, precludes the idea of their having drifted 

 from other tracks into the hollow at Cartsdyke since the time 

 these delicate organisms became attached. 



PAPER READ. 



On Petromyzon fluviatiUs, and its mode of 'preying on Coregonus 

 clupeoides. By Mr David Eobertson, F.G.S. 



About a month ago I found on Loch Lomond a full-sized dead 

 Powan {Coregonus chqjeoides, Lacep.), having two abraded holes 

 about the size of the point of the fore-hnger, one on each side of 

 the shoulder. My boatman said that these holes, or bites as he 

 called them, were made by an eel, which he assured me he often 

 found hanging to a Powan. Shortly afterwards we came upon 

 another Powan of smaller size, floating on the water, belly up, 

 with an eel hanging to it. I managed by means of a hand-net 

 to get them both into the boat, where the eel at once let go its 

 hold. The Powan was dead, but had all the appearance of being 

 only newly so. This so-called eel was the Lampern {Petromyzon 

 fluviatiUs, Linn.) In looking over what books were accessible to 



