THE NAUTILUS AND ITS RELATIVES 



Year after year beheld the silent toil 



That spread his lustrous coil ; 



Still, as the spiral grew 



He left the past year's dwelling for the new, 

 Stole with soft step its shining archway through, 



Built up its idle door, 

 Stretched in his last-found home and knew 



The old no more. 



HOLMES, The Chambered Nautilus. 



On the day following our excursion after squids, we again visited 

 Boston in company with Professor Parker, and the entire clay was spent 

 in that city and in Cambridge, studying the specimens in the museums. 

 From the Professor we obtained the following information concerning 

 the various kinds of squids and their relatives. 



The highest group of mollusks belongs to the class Cephalopoda, 

 which signifies head-footed, the name having been given to them because 

 the head is surrounded by a circle of tentacles which act as both arms 

 and feet. The general plan of the animal is that of a sac, the head 

 protruding from the anterior end, and ending, as before stated, in a circle 

 of eight or ten arms. The eye is wonderfully developed, and the 

 nervous system is very complex. As the brain is protected by a cartil- 

 a : nous box, they resemble the vertebrate animals in this one respect. 

 In this class, the majority of the species that possess shells are 

 extinct, there being only from a dozen to fifteen species living at the 

 present time. The Ammonite is an excellent example of the extinct 



Cephalopoda. 



The most familiar member of this family is the pearly nautilus, Nau- 

 tilus pompilius, the shell of which may be found on the mantelpiece or 

 what-not of many dwellings. The shell of the Nautilus is formed in a 

 spiral and is made r. t of many chambers, all connected by a tube called 

 a siphuncle. The outer chamber contains the animal, and is hence 

 called the living chamber. This shell is called the pearly nautilus, but 

 the pearly tints cannot be seen until the outer layer, which is yellowish 

 white with brown markings, is taken off, when the exquisite, rainbow- 



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