( 34 ) 



Operculum bivalved. 



DIVISION XXIV. ANNEXE 



GEN Kit A. 



L Tekedo. Lin. M. 



A testaceous, cylindri- 

 cal, twisted tube, open 

 at each end. Shell bival- 

 ved, situated posteriorly 

 without the tube Fig. 121, 



2. Aspercillum. Lam. M. 



Tube insensibly nar- 

 rowing towards its ante- 

 rior part, where it is 

 open, and widening into 

 a club at the oiher end, 

 which has two valves in- 

 crusted inlo its side ; the 

 terminal disk is pierced 

 with scatle:ed sub-tubu- 

 lar holes, having a fissure 

 in the centre. (2) Fig. 126. 



(1) They are found in wood which has been sunk in the sea. The Popart of 

 Adanson belongs to them ; their shell is enclosed in a thin sheath, which remains 

 attached to the stony bodies in which they are buried. They do much mischief 

 to vessels and piles driven into the sea. They are supposed to bury themselves 

 deeper as they grow bigger, and to hollow out the wood with their valves; their 

 tubes always remaining at the opening, for water and food ; their passage is 

 lined with a calcareous crust, which exudes from them and forms a sort of 

 tubulous shell. They are said to have been brought from the Torrid Zone to 

 Holland, and more than once to have threatened that country with destruction, 

 by destroying the wood of the dykes. Foss. in the London Clay. <« r 



(2) The common species is from 8 to 10 inches long, and is said to be found 

 attached by its smaller end to the rocks of the Indian seas; which M. Lamarck 

 denies by asserting that this end is necessarily open, The Red Sea, Indian Seas, 

 Kew Holland. 



11. .Pyagoma. Savivnj-. 

 M. 



Valves united, having 

 the appearance of an uni- 

 valve, sub-globulous, ven- 

 tricose, pieiced at the 

 summit, opening small, 

 and elliptic. Fig. 113. 



2 operculiferous bo- 

 dies, adhering to the sides 

 of* the tubes of the ani- 

 mal. (1) 



