30 



Shell Life 



and prominent, placed on the sides of the head below 

 the arms. There is no external shell, but in the 



mantle there is the one 

 familiarly known as 

 " C u 1 1 1 e - bo n e," more 

 especially to bird fanciers. 

 This consists of a thin 

 hard shield, filled with 

 thin soft plates of porous 

 lime. 



The Sepia can walk 

 liead downwards by the 

 aid of its arms, whose 

 inner sui-faces are covered 

 with powerful suckers ; it 

 can also swim rapidly 

 backwards by violently 

 ejecting water from the 

 gill-chamber through a 

 tube called the funnel. 

 The opening by which 

 water is admitted to the pair of gills is in front 

 below the arms. The sexes are distinct, and the 

 young are produced from eggs attached in great 

 clusters to seaweeds. 



These three creatures — the Garden Snail, the 

 Swan Mussel, and the Sepia — stand as types of 

 the three principal classes of moUusks with which 

 we have to deal in the following pages ; and we 

 have so introduced them on the principle of pro- 

 ceeding from the most generally known to the less 

 known. Regarded from the point of view of the 

 systematic naturalist, the Sepia, as tlie highest 



Sepia 



