152 OBSERVATIONS ON THE ARGONAUT. 



their shell they are not capable of forming another, but die. 

 Certain, now, that the experiment I intended to make was 

 new, I broke in several places the shells of twenty-six indivi- 

 duals, and to my great satisfaction found after thirteen days 

 the fractures healed in all those which survived, which were 

 not more than three. The newly secreted portion is stouter 

 than the shell itself, but it is not so white, and also looks a 

 little rough and disturbed, neither does it present the usual 

 risings, and instead of ribs, it has some longitudinal furrows. 



Being desirous of observing in what manner the poulp op- 

 erated in repairing the broken shell, I took one the day after 

 the first experiment, and found that the aperture was covered 

 by a thin glutinous lamina, which, somewhat in the way of a 

 cobweb, unites the two margins of the broken shell. The 

 next day the lamina became thickened to a certain degree, 

 and more opaque, till at the end of ten or twelve days the new 

 piece had become quite calcareous. Whilst in the act of 

 mending the fractures in the shell, I am quite sure the argo- 

 naut applied the sails to the shell, and wrinkled them upon 

 it, and by this movement I considered the glutinous secretion, 

 which finally became calcareous substance, to be verified. 



As yet I have shewn the argonaut to be the constructor 

 of its shell, because it can repair it, is like other Testacea, 

 which are not more expert than the argonaut in hiding the 

 appearance of the patch mended : but a circumstance in my 

 mollusc has appeared new to me, and I do not know that it 

 has ever been observed in other Testacea. This is, that when- 

 ever the poulp can find pieces of other argonaut shells in the 

 place where it is going to mend its own, by means of its sail 

 arm it takes the piece of broken shell which it believes capa- 

 ble of filling up the space fractured, and holds it there till 

 it has excreted the material necessary to attach it firmly, 

 thus sparing itself the trouble of filling up a large aperture by 

 its own secretion. 



After such a series of experiments it seems to me to be suf- 

 ficiently proved that the poulp of the argonaut is the fabrica- 

 tor of the shell in which it lives, and out of which it cannot 

 long exist. 



In presenting to you, gentlemen, a succinct account of the 

 results of my experiments, I have claimed no more than to 

 merit your indulgence, and shall feel pleased if I have obtain- 

 ed it, if only for my good intentions. 



The illustrious members Prof. Carmelo Maravigna, Prof. 

 Anastasio Cocco, and Prof. Carlo Gemmellaro, encouraged 

 me to prosecute my researches so far, and having been ho- 

 noured by this illustrious society with the title of Correspond- 



