44 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



Firth of Clyde, published in 1878, accounted for these 

 valves on the supposition either that they had, like 

 Pecten islandicus when it occurs with us, been 

 washed out of a post-tertiary bed, or that they 

 might have been thrown overboard from some 

 fishing-boat returning from the Irish coast. 



The next reported occurrence of the shell was by 

 myself. In dredging, in 1878, in 20 fathoms at 

 Portavadie, opposite Tarbert, in Loch Fyne, there 

 came up a fragment of which the unmistakable 

 umbo or beak formed a part. This fragment was 

 shown both to Mr. David Robertson, our President, 

 and to Mr. Alfred Brown, and was admitted by 

 them to be a piece of Isocardia cor. 



The next record is by Dr. J. R. Henderson, now 

 Professor of Biology in the Christian College, Madras. 

 In the Scottish Naturalist of January, 1885, he tells 

 us that while trawling in the Medusa in 1884, in 20 

 fathoms off the north end of Holy Island, Arran, 

 there were brought up one or two examples of this 

 shell, perfect and fresh, but without the animal; 

 and he also subsequently obtained valves in 60 

 fathoms water, at some distance from Whiting Bay. 



It was rather remarkable that these examples 

 should have been met with, for Prof. Herdman, who 

 worked about Holy Island for a month in the 

 autumn of 1879, and whose carefully drawn-up lists 

 of all the Invertebrate groups were laid before the 

 Royal Physical Society on 21st January and 15th 

 December, 1880, makes no reference to Isocardia. 



The next Clyde record is of especial interest, as it 

 is the one which at last established Isocardia as a 

 denizen of our own estuary, the previously-obtained 

 untenanted dwellings of the animal not sufficing to 

 do that. At a meeting of this Society in August of 

 last year, a short paper by Mr. David Robertson was 

 read which described the obtaining of living speci- 

 mens of Isocardia in from 90 to 98 fathoms water, 

 between the Cumbrae Lighthouse and Brodick, on a 

 bottom of soft mud. These were obtained at two 



