Mollusks. 5709 



pretty firm, must have been buried there above twenty feet under- 

 neath the present surface, during some great convulsion, which must 

 have taken place before a house of the town of Ayr was built, and at 

 a period to which the history of Ayrshire does not extend." — Lands. 

 p. 84. 



Teredo megotara. This rare ship-worm is included in Dr. Lands- 

 borough's list of Arran Mollusca. 



Xylophaga dorsalis. Abundant in and around Ardrossan docks, in 

 company with Teredo norvagica. Major Martin sent specimens 

 from this locality to Mr. W. Thompson, who, in 1847, published an 

 interesting account of the species in the ' Annals of Natural History,' 

 (vide also ' F. & H.' vol. i. p. 93). There is a good specimen of the 

 Xylophagse, in situ, from Ardrossan, in the British Museum. Mr. 

 Hennedy states that " Xylophaga dorsalis was found last year (1851) 

 when Gourock Quay was repairing : it inhabited the piles, and, along 

 with Limnoria terebrans, had completely destroyed the portion 

 under water. Timber, thoroughly perforated with these pests, is 

 often cast ashore in the vicinity of Gourock." — The Naturalist, 

 vol. ii. p. 88. While the Teredo norvagica bores with the grain, 

 penetrating into the very heart of the wood, the Xylophaga bores 

 across the grain, and rarely excavates deeper than an inch from 

 the surface. 



*Pholas dactylus. Clyde (Smith), F. $ H. 



* „ crispata. Bute, Clyde, Smith. It is far from rare in 

 Lamlash Bay, where it may be found near low water-mark by turning 

 over the pieces of shale and examining them for its excavations. It 

 usually bores from beneath upwards, and when it has perforated the 

 stone through to the upper side, which it does, as the stones are not 

 very thick, it dies. It does not grow to a large size in this locality ; 

 my finest specimen does not exceed an inch and three-quarters 

 in length. " Pholas crispata occurs plentifully in clay at the Castle 

 and in several places further down the Clyde." — Hennedy, 'The 

 Naturalist] vol. ii. p. 88. On one occasion I observed two or three 

 Pholades burrowing in the Red Sandstone, just west of Karnes Bay, 

 Isle of Cumbrae: having no instrument with me I could not then 

 procure them, and left them hoping to return another day and extract 

 them; unfortunately, however, I neglected to mark the exact spot, and 

 although I many times searched I never again fell in with them. 

 From the view I had of the siphons, I believe these individuals 

 to have been crispata, but of this I cannot speak with certainty. 



