Rev. D. Landsborough's Account of a Dredging Excursion. 251 



the auricles are unequal and acute ; the intercostal spaces are, like 

 the ridges, destitute of striae or other markings, and each termi- 

 nates in two acute teeth ; internally the colour is pure white with 

 the muscular impressions large and well-defined. The substance 

 of the shell is singularly thin and delicate. 



Length \^~ inch; height 1^; breadth ~. 



It is difficult to say what species this highly elegant and inter- 

 esting shell is most allied to. In form it perhaps approaches 

 nighest P. opercularis, but from it, as will be seen, it differs in the 

 total absence of striae or other markings which are so constant 

 in all the varieties of the latter shell ; and in the inequality of the 

 auricles. The number of ribs furnish additional distinctive marks, 

 not to speak of the marginal toothing, which latter remarkable 

 character indeed, combined with the great delicacy and satiny- 

 like surface of the shell, separates it from every other species with 

 which I am acquainted. 



The single specimen from which the above description was 

 drawn up, was brought up by the fishing lines off Aberdeen in 

 the beginning of February 1845, and was given me by a Foot Dee 

 fisherman. The shell was quite fresh and perfect, and according 

 to the fisherman, contained the animal ; indeed a portion of the 

 adductor muscle still remained attached when I procured it. Its 

 natural habitat was probably gravelly, as it was accompanied by 

 Buccinum undatum and dead shells of Astarte elliptica and Tellina 

 proxima. 



I have much pleasure in dedicating this beautiful shell to my 

 esteemed friend and master in science Dr. MacGillivray, whose 

 merits need no panegyric of mine, and who by the publication of 

 his admirable ^ Mollusca of Aberdeenshire ' has set an example 

 which I should much like to see more extensively followed. 



XXXII. — Account of a Dredging Excursion. By the Rev. David 

 Landsborough. 



A CRUISE is rather an anomalous event in the life of a sober 

 country minister, and a dredging excursion is what seldom falls 

 to the lot of even zealous naturalists. Few have at their com- 

 mand the vessel, the sailors, and the dredging apparatus ; and 

 most of us are thankful if we can find time for an occasional 

 ramble for a few hours, in a wild glen, or on the mountain side, 

 or on the teeming shore of the beautiful sea. Great then was 

 my happiness in being invited to spend a few days in dredging 

 along with Mr. Smith of Jordan Hill, in his nice little yacht the 

 Raven ; a pleasure I had not enjoyed since I had been with him 

 in his still nicer yacht the Amethyst. 



T2 



