MYA. 69 



dently derived from the Danish word " smor," or butter, 

 which is expressive of the rich flavour of the animal. It 

 is eaten and much esteemed not only by the natives of 

 all northern countries, but by the walrus, arctic fox, and 

 the grey-headed duck or King Eider in Greenland ; and 

 there, according to Fabricius, the shell is sometimes used 

 as a spoon. Torell informs me that when he was last 

 at Spitzbergen he took from the stomach of a walrus, 

 that had been recently killed, a great number of the 

 feet of M. truncata, the other parts having been appa- 

 rently digested or got rid of. He is of opinion that the 

 walrus rakes up the My a from the mud by means of its 

 long tusks, and that, after crushing the shell between 

 its molar teeth, it spits out the fragments, as well as the 

 leathery tube. The cod on the North- American fishing- 

 banks seem to be equally fond of this mollusk ; but it is 

 not so easy to say how they procure it. M. truncata is 

 often buried from 8 to 10 inches below the sea-bottom ; 

 and it does not seem to be capable of changing its habi- 

 tation. The young occasionally occupy the deserted 

 holes of Saxicava. They are more active than their 

 parents, and exhibit a remarkable precocity of instinct. 

 In Mr. Osier's well-known paper " On Burrowing and 

 -Boring Marine Animals " (Phil. Trans. 1826) he says, 

 "On examining a My a truncata, dug up on the pre- 

 ceding day, and which, when grown, will not attempt 

 to burrow, I found two young ones, entangled in the 

 cuticle at the extremity of the syphon, scarcely more 

 than a line in length, and apparently but just excluded. 

 Being placed on sand in a glass of sea-water they buried 

 themselves immediately." In this and a later stage of 

 growth the shell has a distinct keel on the posterior 

 angle ; the beaks are calyciform and resemble a Kellia, 

 so that the fry must be of that shape. The half-grown 



