172 MYAD^. 



reys' cab.); " at Rothesay Bay both this and truncata are 

 used by the fishermeu for bait" (Akler); Frith of Forth 

 (E. F.) ; Aberdeenshire, abundant in the Outer Hebrides 

 (Macgillivray). The specimens found in sand are, as 

 Montagu observes, far more smooth and regularly grown 

 than those extracted from gravel, and are covered with a 

 distinct epidermis. They are discovered by a small hole 

 on the surface, through which on pressure the animal ejects 

 a considerable quantity of water. It burrows to the depth 

 of more than a foot. 



The jl/y« arenaria is occasionally found in brackish 

 water, and is then subject to dwarfing and distortion. 

 Such is the condition of the specimens in the Loch of Sten- 

 nis in Orkney, famous for the part it plays in the scenery 

 of Scott's admirable novel of the " Pirate." In that lake 

 we find Lininei, JVeritinte, and other fresh-water Mollusks, 

 along with the Myce^ which now, however, appear to be 

 nearly, if not altogether, extinct. Before they became so, 

 they had greatly diminished in size, and become variously 

 distorted. In this instance the cause is to be sought for 

 in a very recent elevation of the land, which has gradually 

 converted what was originally an arm of the sea into a 

 brackish pool, only occasionally flooded with salt water, 

 and probably destined eventually to become a fresh-water 

 lake. In Mr. Cuming's collection are some remarkably 

 distorted My^s of this species from the sluices at Ostend, 

 where their deformities are most likely also due to the 

 pernicious influence of fresh water. To the same cause we 

 may attribute the numerous and singular varieties of this 

 shell, such as the so-called species, M. lata and puUus, 

 found in the mamaliferous crag of the east of England, a 

 formation in which many of the mollusca are deformed. 

 The melting of the icebergs which then chilled our region 



