CEPHALOPODA. 



29 



That these creatures repair their shells as well as form 

 them, is shown in the following interesting extract from 

 Silliman's Journal for July, 1848 : — " Tn the collection 

 of shells in the cabinet of Amhurst College is an indi- 

 vidual of the Argonauta Argo, which appears to furnish an 

 additional argument in support of the opinions which are 

 based on the researches of Madame Power. In this shell, 

 a portion has been broken out near the middle of the left 

 side, and not far from the sinus of the aperture. The 

 opening was of a semilunar form, about If inch long, with 

 an average breadth of half an inch. A new deposit of 

 testaceous substance, together with a broken fragment, 

 has closed the opening in the rude manner common in the 

 shells of mollusca. But the most extraordinary circum- 

 stance is this ; that a fragment which was broken out in 

 the accident which befel the animal, now constitutes two- 

 thirds of the repaired portion; and that the originally 

 inner surface is now the outer surface, as is evident from 

 its concavity, style of undulation, and texture. It is also 

 nearly at right angles to its original position. These facts 

 show that the piece was totally detached from the shell by 

 the accident. We apprehend that such a case could scarcely 

 occur, especially in a shell moving in the water, except in 

 consequence of the functions now ascribed to the vela of 

 the Argonaut. These once reputed sails, performing the 

 less poetic function of clasping and enveloping the shell, 

 prevented the loss of the large fragment. It is obvious, 

 also, that the new deposit of testaceous matter was secreted 

 from the part of the animal within the shell, and not from 

 the vela, since the edges of the original shell around the 

 fracture appear exclusively on the outside. Since none 

 but the original inhabitant could repair it, the case de- 

 scribed is corroborative of the opinion, that the animal 

 usually seen in these shells is the original owner," 



