254 



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

 for nearly half a century, near Berry-Head at the entrance of Tor- 

 bay, have lately been dragged up, filled with magnificent specimens 

 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 i-eceptacle 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 : but it 

 wants the tube with its accessorial valves, is closed and rounded at 

 the hinder part, and attaches itself to the inner surface of its cy- 

 lindrical lodgment, by a tube of suction in the centre of the gape, 

 such as is found in the Gastrochcena Pholadia. There is also a 

 strong round muscular impression in each valve : and from any of 

 the known 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 essentially differs 

 both from the Pholas and the Teredo, in wanting the long curved 

 tooth originating from the hollow under the inner margin of the 

 valves, having only a slender curved process ujjon the cardinal mar- 

 gin 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 magnified 

 at fig. 5 of our plate. 



