180 TEREDINID.E. 



from Dr. Lukis and Mr. Dennis. The proximity of 

 South Carolina to the Gulf of Mexico, and the course 

 of the great " river in the ocean " along the Atlantic 

 coasts of North America, indicated by Captain Maury 

 in his ' Physical Geography of the Sea/ may account 

 for this commixture of different kinds of Teredo in the 

 same piece of floating timber. 



T. megotara is intermediate in size between T. Nor- 

 vegica and T. navalis, from both of which it may easily 

 be known by the large auricle on the posterior side and 

 by the strong and projecting hinge ; the pallets are more 

 like those of T. Norvegica, but they are flatter and of a 

 more delicate texture, with a semicircular impression in 

 front, and shorter stalks ; the sheath is of variable thick- 

 ness, and is sometimes altogether wanting, except at the 

 neck, which is regularly laminated with a siphonal ridge 

 down the middle of each side. The mouth of the sheath 

 in very young specimens is crossed by a slight and 

 curved rib, that separates the tube and resembles the 

 handle of a basket. A specimen which I took out of a 

 piece of Canada pine measured 21 inches from the 

 valves to the pallets. 



I concur with the authors of the ' British Mollusca ' 

 in rejecting the specific name nana, given by Dr. 

 Turton to this species; not only because it is inap- 

 plicable, but also because his description was insuffi- 

 cient and taken from immature and imperfect speci- 

 mens. At the same time I regret that the name which 

 they substituted for it is open to objection as pleonas- 

 tic or redundant, being compounded of two Greek 

 words signifying greatly and large-eared; megalota 

 would be more correct. It is the Bruma delV oceano 

 of Vallisnieri, T. oceani of Sellius, Pholas Teredo of 

 Miiller and Fabricius, T. navalis of Moller, T. dilatata 



