FAMILY TEREDINIDiE — TEREDO. 249 



FAMILY TEREDINID^E. 



Shell either inclosed in a calcareous tube distinct from its valves, or encrusted either par- 

 tially or wholly in it, or projecting beyond it. Marine. 



Obs. This group corresponds with Les Tubicolees of Lamarck, and the Teredinites of 

 Latreille. It comprises at present six genera ; the living representative of one only has yet 

 been observed on the coast of the United States. 



GENUS TEREDO. Linnmus. 



Animal much elongated, vermiform, with the mantle very slender, opened in front and at its 

 lower portion for the passage of the foot. Tubes separate, very short. Mouth small ; la- 

 bial appendices short. Vent at the end of a small tube floating in the cavity of the mantle. 

 Gills ribbon-shaped, united in their whole length in a single line slightly extended into the 

 siphon. A muscular ring at the point of junction of the mantle and tubes, in which is 

 implanted a pair of corneo-calcareous pediculated appendices, acting laterally against each 

 other. Shell bivalve, orbicular, hemispherical, equivalve, terminating behind in a long 

 cylindrical tube. Hinge with a long curved tooth in each valve, inserted under the margin : 

 no lateral teeth nor ligament. Tube cylindrical, straight or flexuous, closed with age at 

 the buccal extremity. 



Teredo navalis. 



PLATE XXXIV. FIG. 325. A. B. o. 



(STATE COLLECTION.) 



Teredo navalis. Linn. Syst. Nat. p. 1267. Russel, Essex Jour. Nat. Hist. Vol. 1, p. 49. 

 T. id. Gould, Invertebrata of Mass. p. 26. 



Description. Shell with valves, ear-shaped behind, triangular, forming a circular ring touch- 

 ing each other only at two points (the surface elegantly striated in various directions), each 

 with a triangular projection in front, bending a little inwards ; one of them with a curved 

 denticle on the margin above the teeth : the edges of the ear-shaped processes behind are 

 not detached around the whole of the circumference. Tube more or less flexuous, semicon- 

 camerated behind (See fig. a.). Length of valves, - 5 - - 7; of tube, 5-0 - 6*0. 



This is the well known Ship-worm, which scarcely extends north of the waters of this 

 State. The supplemental valves within the tube, and near the small extremity, are spoon- 

 shaped, convex on the outside and concave within, terminating in a linear elongation (See 

 fig. c). I am indebted to Turton for the figures. Its greatest ravages in our waters, take 

 place in August and September. The long galleries which it excavates are lined with a 

 second kind of tubular shell. 



Fauna — Part 6. 32 



