TEREDO. 175 



of Passages (province of Guipuscoa) on the north coast 

 of Spain ; Toulon (Eydoux and Gay) ; Provence (Martin, 

 fide Petit) ; Algeria (coll. Deshayes) . 



Some valves which I received from the late Dr. Lukis 

 are of a greenish-brown colour -, these he found in oak. 

 He also sent me a piece of a deal plank, which had 

 formed part of a shipping-stage at Alderney, and had 

 been under water for twenty years : the outside was 

 fretted by Chelura terebrans; the interior was full of 

 T. pedicellata ; and through their crowded galleries a 

 huge T. Norvegica pursued its solitary course, but with- 

 out interference on either side. The present species 

 produces at an early age. Its sheath is a beautiful 

 object, the points being imbricated like the segments of 

 the stalk of an Equisetum the orifice in very young 

 specimens resembles a key-hole. Dr. Lukis assured me 

 that this kind caused great destruction in the Govern- 

 ment works and new pier at Alderney : no endeavour 

 was made to prevent or stop it. 



This is not a satisfactory species, because its sole dis- 

 tinction depends on size and the pallets, and it has 

 never been seen in company with T. navalis. The last 

 reason has, of course, a limited value, although it is by 

 no means unimportant when considered in connexion 

 with other circumstances and analogous cases. The 

 pallets are hoe-shaped, with a long handle, and a sepa- 

 rate shelly process or membranous fringe at the other 

 extremity. Fischer conjectured that T. pedicellata 

 might be the young of T. Norvegica or of T. navalis ; but 

 the pallets of each species, when first formed, exhibit 

 exactly the same relative characters as in subsequent 

 stages of growth. 



