190 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



bring to light invertebrate forms previously rare 

 or of unknown occurrence in the Firth. 



The waters washing the Ayrshire coast have not, 

 of late at least, received great attention ; and it was 

 with this impression that last summer three mem- 

 bers of our Society, Mr. D. A. Boyd, Mr. James Steel, 

 and myself, formed the idea of trying the ground 

 lying out from Portincross and due south of the 

 Small C umbrae — a locality situated in the upper 

 reach of the outer portion of the Firth, and in which 

 the depth, a short distance from the shore, gradually 

 increases from 20 to 50 fathoms. The day of our 

 expedition was 24th August. The dredging apparatus 

 used was that belonging to the Society, and consisted 

 of a 9-lb. dredge, with double cheese-cloth bag, 75 

 fathoms of 4-strand manilla rope, two sieves fitting 

 into one other, and two iron buckets ; while each of 

 us, in addition, had his own receptacles for the get- 

 tings of the day. Our craft was an ordinary sub- 

 stantial rowing boat, and we had the presence and 

 assistance of its owner. The day was all that could 

 be desired — calm and not too bright, admitting of 

 operations being carried on uninterruptedly, and 

 without unnecessary fatigue during the hours we 

 were at work. The direction taken was due west 

 from Portincross Castle, and our first hauls were at 

 about a mile from the shore, in 30-fathom water. 

 We then proceeded farther out for half a mile, to a 

 point where the chart indicated 44 fathoms, and 

 here we had three hauls, the dredge working well, 

 and coming up so filled as to tax our powers in 

 lifting it in. 



With regard to the bottom in this quarter, though 

 in the chart it is only at 44 fathoms marked " M ' 

 meaning mud, the area worked over was entirely of 

 a mud presenting the same appearance at all the 

 points. We had fancied that, at the lesser depth at 

 least, the tidal action here would have caused it to 

 be muddy sand and gravel ; but instead, what was 

 brought to the surface was mud of the softest and 



