CONCHII'ERA. 



235 



of tho tube entirely closed by a trapezoidal plate, which tills 

 up the spaco left by the sinus in tho two valves. 



The posterior portion of the tube is of a difl'ercnt consis- 

 tence from the anterior part, liavini; a horny tpxtnro and ap- 

 pearance ; the interior of tho valves is thickly lined with the 

 same testaceous matter as the tubes. Tho testaceous substance 

 is generally so much thickened in front, that it almost entire- 

 ly conceals the tooth-liko processes. 



1. Teredina person at a. — The Masque Teredina, pi. 

 XCVI. figs. U, 15, 2-i, 26, 27, 28. 



T. personala. Sowerby, I. p. 232, pi. 1 02, figs. 1 to 4. 



Valves transversely striated on the posterior side ; anterior 

 side smooth, with a few lines of growth ; the accessory plate 

 pentangular and smooth ; tube as thick as the valves. 



In tho London Clay, Sheppy and Epernay. 



Genus LXXII.— TEREDO.— Zi««<c«s. 



Shell equivalve, inequilateral, and orbicular, with a subulate 

 process in front, and gaping at both sides ; anterior opening 

 angular at the back, and the posterior one rounded in front ; 

 an elongated, curved, tooth-like process emanates from the in- 

 side, in both valves, protruding from the beaks ; anterior mus- 

 cular impression situate upon the subulate process ; shell 

 placed on the auterior extremity of a testaceous accessory tube, 

 which is secreted by the animal in its progress through wood, 

 &c., and forms a lining to tho perforated cavity, becoming 

 gradually wider as the animal advances, and is frequently fur- 

 nished internally with a vaulted septa ; aperture of tho tube 

 round, and posteriorly divided into a double tube, which the 

 animal has the power of closing by means of two palmate, 

 sometimes pcnnated apercula. 



1. Teredo navalis. — The, Ship Teredo, pi. XCVI. fig. 13. 

 T. navalu. Brown, 111. Rec. Conch. Bri\ p. 116, pi. 50, 



figs. 1 to 7. 



Valves triangular, ear-shaped behind, and hemispherical 

 when closed, with a curved tooth on the margin of the umbo- 

 nal region ; surface of the valves striated in various directions, 

 each with a triangular projection in front, inclining inwards 

 and conforming to the angular form of the valves, with a 

 lengthened flat curved tooth, projecting inwards under the 

 beaJ^s ; tube flexous, and without any regular form. 



The Coral Crag, Sutton. 



2. Teredo a.mpuisbjena. — The Blind- Worm Teredo, pi. 

 XCVI. figs. 16-19. 



T. ain/i/iisbwna. Sowerby, VII. p. 17, pi. 618. 



Valves unknown ; tube much lengthened, tapering, tortu- 

 ous, strong, and smooth, composed of short segments with 

 sharp edges, and concave imbricated surfaces. 



The London Clay, Marham and Gayton. 



3. Teredo antenaut^e.— PI. XCVI. figs. 31-33. 



T. anienautw. Sowerby, I. p. 231, pi. 102. 



Valves transversely striated, those on the anterior side 

 numerous, zig-zag, minutely toothed, smooth, with dorsal 

 posterior accessory valves testaceous. 



The London Clay, Sheppy and Nuneham. 



Genus LXXIII.—FISTULANA.—flrM^«tVr«. 



Shell cqnivalve, inecpiilatcral, transversely elongated, and 

 gaping widely at the basal margin ; anterior side very short; 

 valves attached by a ligament, and situate in the lower part of 

 a testaceous tube, which is closed at the lower or anterior ex- 

 tremity, and to which they are confined by the septum, and 

 open at the centre ; the posterior end attenuated and open. 



1. FisTULANA AMPULLARiA. — The Ample Fistulana, pi. 

 XCVL figs. 9-12. 



F. ampullaria. Deshayes, Coq. Fos. pi. I. figs. 17-21. 



Sheath sandy, bottle-shaped, and continuous ; aperture in- 

 ternally bicarinated ; shell ovate, gaping widely, the hiatus 

 oval, with sinuosities. 



The London Clay, Barton. 



Genus LXXIV.—CLAVAGELLA.—Z,a»n<^rc)^. 



Shell consisting of a testaceous tube, somewhat attenuated, 

 and open at its anterior extremity, irregularly ovate, sub-cem- 

 pressed, claviforni, and closed at its lower end, excepting by 

 a number of irregularly formed minute tubes ; clavate termin- 

 ation provided with an irregular, thin, flattened, pearly adhe- 

 rent valve, on one side, with a loose, extremely thin valve at 

 the bottom of tho tube, which is supposed to be united to the 

 fixed valve by a ligament in a living state ; an irregular mus- 

 cular impression near one side. 



The tube of the Clavagella; is sometimes free, and, at others, 

 it lines sub-marine bodies, such as madrepores, stones, and 

 clay. 



1. Clavagella coronata. — The Crowned Clavagella, pi. 

 XCVL figs. 35-37. 



C. coronata. Deshayes, Coq. Foss. I. p. 8, pi. 5, figs. 15, 

 16. Sowerby, V. p. 128, pi. 480. 



Tube straight, elongated, club-shaped, and crowned with 

 about eight antler-like branched tubes, arranged in sets ; the 

 included valves oblong, sulcated, with strong lines of growth, 

 and gaping widely ; beaks acute and large ; inside of both 

 valves pearlaccous ; the sulcus which divides tho two sets of 

 tubes, with a branch that descends the side of the sheath in 

 which the free valve is contained. 



The London Clay, Hampshire. 



