444 



CEPHALOPODA. 



and their membranes, so as partially to uncover the shell in front, 

 as is represented in the figure (Jig- 207). 



Fig. 207. 



There is little doubt that the vela of the Argonaut, which thus 

 envelope its abode, are the organs employed in constructing the 

 brittle fabric, and the agents whereby fractures and wounds in the 

 shell are repaired and filled up. 



The positive experiments of Madame Power* leave no doubts 

 upon the subject ; for not only did that lady, by rearing young 

 Argonauts from the egg, watch the first appearance and earliest 

 growth of the shell, but, by breaking the testaceous covering of 

 adult specimens, she found that they could readily repair the 

 damage inflicted. Being desirous of observing the manner in 

 which this operation was accomplished, the lady to whom science 

 is indebted for these interesting researches examined an individual 

 on the day after its shell had been intentionally broken, and found 

 that the aperture was already covered by a thin glutinous lamella, 

 which, although as yet as delicate as a cobweb, united the margins 

 of the fracture. The next day the lamina had become thickened 

 to a certain degree and more opaque ; till at length, at the end of 

 ten or twelve days, the new piece had become quite calcareous. 

 Madame Power is likewise certain that, while in the act of mend- 

 ing the fractures, the Argonaut applied its vela to the exterior of 

 the shell, and wrinkled them upon it ; whence they may naturally 

 be regarded as being the source from which the glutinous secretion 

 that finally became hardened into shell proceeded. 



* Magazine of Natural History, April 1839. Observations on the Poulpe of the 

 Argonaut, by Madame Jeannelte Power. 



