80 PIIOLADID.E. 



there is rather a large triangular depressed basal surface, and 

 in the young, a small, but deep incurvation in the middle. 



The tubes are strong, and without concameration. 



The finest specimens we have ever met with were ob- 

 tained by Mr. Hanley from timber, which, having formed a 

 portion of the piles of the pier at Heme Bay, in Kent, had 

 been removed in consequence of its destruction by these 

 animals. One tube was nearly half a yard in length, and 

 the valves rather more than half an inch in diameter in 

 each direction, their length and breadth being nearly equal. 

 The locality mentioned by Turton is simply " wood in Tor- 

 bay :" to this may be added, — from wood drifted on shore 

 at Exmouth, (Clark;) from drifted Avood in Swansea Bay, 

 (Jeffreys;) and from some stakes near the jetty at Broad- 

 stairs, (Metcalfe.) 



Species not proved to be of British origin. 

 4. T. RIPENNATA, TurtOH. 



Valves with the body or medial portion narrow and elongated. 

 Auricle typically projecting higher than the beaks : its upper inter- 

 nal edge most strongly reflected outwards ; the lower internal edge 

 scarcely sloping, and projecting shelf-fashion over the body. Tri- 

 angular area extending as low down as the auricle, not large, its 

 outer edge very oblique ; tooth-like apophysis greatly slanting 

 posteriorwards. Pallets very large, quill-shaped, of a spongy 

 texture. 



Plate IV. figs. 9, 10, 11. 



Teredo lipennata^ Turton, Conch. Dictionarj-, p. 184, f. 38, 39, 40. — Turt. 

 Dithyra. Britann. p. 15. — Flem. Brit. Anim. p. 454; Brit. 

 Marine Conch, p. 28.— Brown, 111. Conch. G. Brit. p. 1 IG. 

 —Gray, Philosoph. Magaz. (18'27,) p. 411. — Hanley, 111. 

 and Dcsc. Cat. Recent Sh. p. 4; suppl. pi. 9, f. 51. 

 „ navalis{?), Speng. Skrivt.af Naturhis. Selsk. vol. ii. pt. 1 , pi. 2, f. 1 , 2, 3, A. 



The indigenousness of this very interesting ship-worm is 

 by no means .satisfactorily established, although, from its 

 being frequently found alive in floating wood, it is by no 



