1 >-; 



CHAMBERED NAUTILUS. Nautilus fompiUwt 



In them, the shell is very delicate, and is rolled into a spiral form, something like the 

 proboscis of an elephant when curled up. These shells are very common on the shores of 

 New Zealand, where they are scattered in thousands, and are sometimes thrown on the 

 southern shores of England by the waves of the Gulf Stream. Yet the animal which formed 

 the shell is extremely rare, and is very seldom found except in a very fragmentary and 

 battered condition. 



ANOTHER order of ccphalopods is called by the name of Tetrabranchiata, or Four- 

 gilled animals, because the organs of respiration are composed of four branchife. These 

 creatures possess a very strong external shell, which is divided into a series of gradually 

 increasing compartments connected together by a central tube called the siphuncle. As 

 the animal grows, it continues to enlarge its home, so that its age can be inferred from the 

 number of chambers comprising its shell. 



In former times these creatures were very abundant, but in our day the only known 

 living representative is the CHAMBERED or PEARLY NAUTILUS, a section of which is shown 

 in the illustration in order to exhibit the beautiful spiral home in which the creature resides, 

 and the structure of the chambers, together with their connexion by means of the siphuncle. 



While the animal still lives, the short tubes that pass through the walls of the chambers 

 are connected by membranous pipes, and even in a specimen that has been long dead, 

 these connecting links hold their places, provided that the shell has not been subjected to 

 severe shocks. In one of these shells now before me, which I have very cautiously opened, 

 the whole series of membranous tubes can be seen in their places, black and shrivelled 

 externally, but perfect tubes nevertheless. 



At the left-hand of the illustration the animal rcay be seen as it appears when lying 

 in its shell, the eye just peering from the edge, the points of the retracted tentacles visible, 



