5 70S Mollusks. 



Ascidia virginea. I met with several examples of this, as it were, 

 blood-stained species, off Cumbrae, Lamlash, Lands, p. 34. 



„ parallelogramma. A beautiful species ; remarkable for the 

 numerous star-like bright gamboge-yellow spots with which it 

 is adorned ; only one specimen occurred to me. 



„ prunum. Common on various seaweeds growing in rock- 

 pools, at extreme low water-mark, Allans, Cumbrae. 



„ echinata. Very rare, deep water, off Cumbrae. 

 Cynthia rustica [Ascidia rustica). Dr. Landsborough mentions 

 this species, under the name of Ascidia rustica, as having been 

 dredged near the Corrigils, Isle of Arran, by Major Martin, Lands. 

 p. 49. 



Fam. IV. Pelonaiada. 



Pelonaia corrugata. The Firth of Clyde can boast of having both 

 the British representatives of this singular genus occurring in its 

 waters ; I took a single specimen of the present species off Shell Bay, 

 Cumbrae, in about twelve fathoms. 



., glabra. " Dredged in seven fathoms water, in mud, 

 Rothesay Bay," F. $ H. 



Div. II. Lamellibranchiata. 



Fam. I. PJtoladidw. 



Teredo norvagica (Teredo navalis). The first notice of this spe- 

 cies occurring in the Clyde district was that of Mr. Smith, who, in his 

 Catalogue, published in 1838, recorded it as found in wood in 

 the Clyde. It has since that time done great injury to the docks 

 at Ardrossan, in which situation it was first found by Major Martin. 

 I was enabled to procure some very fine, though dead, examples from 

 a portion of. the old dock-gates, which had been removed in con- 

 sequence of the attacks of the Teredo. Dr. Landsborough writes of 

 this species, " their strong calcareous tubes are not often seen more 

 than a foot in length, but Mr. W. Thompson mentions that at Port- 

 patrick they have, in some cases, attained the extraordinary length of 

 nearly two feet and a half: the greatest diameter at the larger end is 

 seven-eighths of an inch ; at the smaller from one and a half to two 

 lines. In these cases the valves of the shells were large in proportion, 

 being three-quarters of an inch in diameter. The largest tubes I ever 

 met with were found by me in a quarry at Content, near Ayr; they 

 were in beams of timber like masts of vessels, which though still 



