254 



ADDENDA. 



Fragments of a wreck, known to have been buried in the ocean 

 for nearly half a century, near Berry- Head at (he entrance of 

 Torbay, have lately been dragged up, filled with magnificent spe- 

 cimens of the Teredo navalis, and this shell, in their most perfect 

 state. 



Like the Teredo it inhabits the interior of wood which has been 

 some time under salt water, penetrating to the depth of from half 

 an inch to an inch, forming for itself an oval receptacle or cavity, 

 and having a very small and single external orifice. 



The valves are shaped like those of Teredo, being furnished 

 with a triangular striated projection in front of the head of each : 

 biit it wants the tube with its accessorial valves, is closed and 

 rounded at the hinder part, and attaches itself to the inner sur- 

 face of its cylindrical lodgment, by a tube of suction in the centre 

 of the gape, such as is found in the Gastrochaina Pholadia. 

 There is also a strong round muscular impression in each valve : 

 and from any of the knowa species of the Teredo, the valves 

 may be distinguished by the internal longitudinal rib. 



Its habitation in wood naturally separates it from the Pholas, 

 from which it also differs in the triangular striated projection at 

 the top of each valve, a character always present in the piercers 

 of wood, and never in the corroders of stone. And it most essen- 

 tially differs both from the Pholas and the Teredo, in wanting 

 the long curved tooth originating from the hollow under tlie 

 inner margin of the valves, having only a slender curved process 

 upon the cardinal margin itself, meeting a smaller and slightly 

 cloven one in the opposite valve. 



At the hinge on the back are a pair of accessorial valves, some- 

 thing resembling the foliations of a calyx, represented as mag- 

 nified at fig. 5 of our plate. 



