36 X.EPAS. 



fat of the whale, and preserved in spirits. That there 

 are twenty-five of the L. Diadema in this situation, is 

 certainly true ; but in what part of the Museum he per- 

 ceived the L. balcenaris grouped in a similar manner, 

 we are at a loss to discover. 



Dufresne's figure has a quadrivalve operculum, sur- 

 rounded by a ligament which connects it with the 

 shell. If this be correct, (and he tells us he furnished 

 the artist with a shell for the purpose,) it will at 

 once mark the distinction between this and the pre- 

 ceding species, which has an operculum of two small 

 valves only, surrounded by membrane. 



The Li. balcenaris buries itself to a certain depth ia 

 the skin of the whale, and when the shell is separated 

 from the animal, it will be partly covered with a portion 

 of the skin, which gives it a black and resinous appear- 

 ance. It may, however, be readily cleaned of this mat- 

 ter ; but the line of separation always remains visible, 

 and may be seen in figure 1 and 2, encircling the shell 

 towards the upper part. 



The dissimilarity in appearance between fig. 1 and 2, 

 may possibly lead to the supposition that they are 

 distinct species, but it is age alone which makes the 

 alteration, fig. 2 being a young shell. 



