EXCAVATORS. 347 



from the Teredo in that it bores against the grain 

 of the wood in a diagonal manner. The perfora- 

 tions of the two species may be observed in the 

 same piece of timber, for they seem to labour har- 

 moniously together in the work of destruction. 

 Many of the chambers have been found an inch 

 and a half in length, whilst the largest shells ob- 

 served are five and a half lines in length. 



Dr. G. C. Wallich has also borne testimony to the 

 boring operations of minute Annelids at great depths 

 in the sea, for he records that he "has met with 

 several examples of Foraminiferous shells, brought 

 up from the greatest depths, perforated, in all proba- 

 bility, by the minute boring Annelids that construct 

 and inhabit the tubes of which he had made mention. 

 The extreme delicacy of the inhabitants of these 

 tubes has, as yet, completely bafHed him in all his 

 attempts to extract them, and determine their char- 

 acter. In addition, however, to the tubes, formed in so 

 singular a manner, of innumerable Globigerina shells 

 cemented together, there also occurred other tubes, 

 in which the internal layer was a cylinder of tough 

 membraneous material, with a rich sienna tint, 

 whilst its outer surface was strengthened and pro- 

 tected, partly by numerous Globigerina shells, as in 

 the previous case, and partly by a layer of siliceous 

 spicules, probably derived from some minute sponge. 

 The perforations in the shells were invariably of 



