276 



MOLLUSC A. 



III.— SEPIA. 



Phylum 

 Class 



MOLLUSCA (p. 282). 



Cephalopoda (p. 284). 



Sepia officinalis is a large mollusc, often nearly a foot 

 in length. It is found commonly round our coasts, though 

 more abundant in the south. It lives a free, roaming, pelagic 

 life, and is a voracious flesh-eater. Its dried shell is often 

 found cast up on the shore. The animal consists of a head 

 and body. The body is flattened and shield-shaped, with a 

 lateral expansion or fin along each 

 Fig. 194.— Dorsal View edge. The head has ten tentacles, 

 OF THE Common Cuttle of which the fourth pair are as long 

 [Sepia officinalis) y.\. ^s the body and bear a pad of 

 suckers at the end. The other 

 eight have four rows of small 

 suckers on their inner surface. A 

 dead ^'cuttle" appears of a dull 

 white colour with patches of drab, 

 but in life there is a beautiful play 

 of colour and light over the whole 

 surface of the body. This is 

 caused by a number of chromato- 

 phores or pigment cells which are 

 actively contractile, and hence can 

 alter their extent. The result is 

 an ever-changing colour and irid- 

 escence. In a general way, the 

 upper surface of the body is of a 

 dark brown hue. It is horizontally 

 striped with irregular bands of white and the fins are 

 similarly dotted with white. The dorsal surface of the 

 head is also brown. The tentacles and the whole under- 

 surface are pearly white. Sepia is piano-symmetric to a 

 marked degree, and there is no trace of torsion as in the 

 snail. The mouth is situated between the tentacles and 

 is armed by a pair of powerful horny jaws or beaks, not 

 unlike those of some parrots in size and appearance. The 

 head is connected to the body by a constricted neck^ 

 around which hangs the front edge of the mantle. 



