CONCHY LI A— DITHYRA. 2. 15 



ear-shaped process behind, the edges of which are not detaclied 

 round the whole of the circumference. 



The tube is more or less flexuous and tapering,' semiconca- 

 merated near the smaller end. The supplemental valves, seated 

 on the inside of the tube and near the smaller extremity, are 

 spoon-shaped, convex on the outside and concave within, termin- 

 ating at one end in a linear elongation which is straight or a little 

 flexuous, and truncate at the other. 



Figi 2 of our plate represents a section of the lower end of the 

 tube, to shew its semiconcamerated structure: and fig. 3 one of 

 the spoon-shaped appendages. 



Teredo valvis postich auriformihus auriculis rejtexis, costa bipenuata, 



ohliqua mai-omali supra denies. 

 Shell with the valves ear-sliaped behind and the auricles 



reflected, an oblique rib on the margin above the teeth. 

 "Teredo bipennata. Tnrton, Conch. Diet. p. 184, fig. 38 to 40. 

 Mus.nost. From timber drifted into Exmouth. 



Shell sometliiiig larger than the last, with the ear-shaped pro- 

 cesses of an oblong sliajje, reflected on their outer margin and 

 detached all round the circumference on the under side. 



The tube is thicker and stronger, without the transverse semi- 

 concamerated i)artitions, and instead of the spoon-shaped valves 

 furnished witli two very long slender appendages, somewhat 

 curved and feathered on each side. 



