1018 PELECYPODA. [Eulamdlibr(ichia. 



Fam. TEREDINIDjE, Fleming. 



Animal vermiform, very long, a small part only (the viscera) pro- 

 tected by the shell ; siphons very long, united to a large extent, and 

 furnished with 2 posterior calcareous pallets, simple or articulated ; 

 heart on the ventral side of the rectum ; a single aorta. 



Shell much reduced, equivalve, auriculate, widely gaping, the valves 

 apposited ventrally only, on the surface of a parietal tubercle ; ad- 

 ductor-scars unequal, the anterior marginal, very small ; pallial line 

 coincident with the valve-margins ; a styloid myophore projecting 

 from the cavity of the beaks ; mantle secreting a calcareous lining 

 to the burrow ; pallets variable in form, the valves without attached 

 accessory plates ; area none ; hinge-margin reflected, edentulous ; 

 ligament absent or obsolete ; anterior adductor degenerate, attached 

 on the anterior edges of the valves, and covered only by the mantle. 



Animal boring chiefly in wood. 



Jura to Recent. 



Genus 1. TEREDO, Linne, 1758. 



Teredo, Linne, Syst. Nat., eel. 10, 1758, 651. Type : T. navalis, L. Xylo- 

 s, Meuschen, 1781. 



Animal with very narrow palpi ; gills narrow, elongated, extending 

 into the branchial siphon ; siphons very long, united, but separated 

 distally, unequal, the orifices fringed ; mantle thick, open in front for 

 the small convex foot ; the dorsal expansion of the mantle covers the 

 apical and dorsal part of the shell. Pallets simple or articulated. 



Anatomy : P. M. Keer. Bijdra,ge tot de Kennis v. d. Paalworm ; 

 Leiden, 1903. 



Shell more or less globose, gaping anteriorly and behind ; valves 

 trilobate, concentrically striated, divided by a single transverse groove ; 

 hinge-margins inflexed anteriorly ; interior with a long, curved process, 

 the styloid apophysis. 



Distributed in all seas. 



Fossil in the Secondary and Tertiary. 



Vernacular Name. Shipworm. 



Remarks. The Teredines are living in wood, which they perforate 

 tortuously, but generally in the direction of the grain ; the perforations 

 are lined by calcareous matter, and the individuals carefully avoid the 

 burrows of their neighbours. They do incalculable, mischief to dikes, 

 submerged piles, and the timber of ships. 



The larvae swim freely about, and are even able to float at the surface 

 of the water. The embryology of Teredo has been studied by B. 

 Hatschek (" Ueber Entwicklungsgeschichte von Teredo " ; Wien, 1880). 



Boring of the Teredo. Mr. Charles Hedley has been discussing the 

 boring of the shipworms at some length (Proc. Austral Assoc. Adv. 

 Sci., 1901, 244). and arrived at the conclusion, based chiefly on the 

 ingenious explanation of Dr. W. H. Dall (Trans. Wagn. Free Inst.. iii, 



