THE PAST AND PRESENT OF THE CUTTLEFISHES. 93 



function of " relation ; " fifthly, to the reproduction and development 

 of the organism, as demonstrating not merely its affinities with other 

 beings, but likewise its evolution ; and lastly, to the distribution -of 

 the animal or group in the world as it at present exists, and likewise 

 in the epochs of the past Our study of the present of the cuttle- 

 fishes may, therefore, resolve itself into a brief notice of these succes- 

 sive features ; the consideration of their present history leading us 

 naturally to correlate that present with their past, in considering the 

 probable evolution of the race. Incidental to such a systematic 

 survey of cuttlefish structure and physiology, we may touch now 

 and then upon matters which have served more than once as the 

 starting-points of a philosophy leading from the consideration of a 

 mere group of interesting animals, to questions bearing upon the 

 origin and modification of the whole universe of life. 



The alimentary tract or digestive system of the cuttlefish race is 

 in every respect of well- developed and complete character. Lower 

 down in the molluscan series the commissariat department is sub- 

 served by a very perfect digestive apparatus, including representa- 

 tives of most of the organs familiar enough to us in higher or 

 vertebrate existence. In the cephalopods we should naturally ex- 

 pect the standard of lower molluscan organisation to be further 

 elaborated ; and this anatomical expectation is justified by the 

 actual details of cuttlefish structure. The mouth opens on the upper 

 surface of the head a disposition of matters already accounted for 

 when considering the relations of the cuttlefish body to that of other 

 molluscs. The mouth-opening is usually bounded by a raised lip, 

 and leads into a cavity containing an elaborate apparatus, analogous 

 to the jaws of higher animals, and by means of which the food of 

 these animals is triturated and divided. An inspection of the masti- 

 cating apparatus of a cuttlefish readily solves the question, " How 

 are the hard shells of their crustacean food broken down? " There 

 exists within the mouth, firstly, a hard horny beak, resembling closely 

 in shape the beak of a parrot, and consisting of two chief divisions, 

 whereof one the front is the smaller, and is overlapped by the 

 hinder beak. Set in action by appropriate muscles, these beaks 

 divide the hard parts of the food with the greatest ease. But a 

 second apparatus of more typical nature likewise exists in these 

 animals. This is the cdontophore, a structure popularly named the 

 "tongue," and which is common to the whelk and snail class, to the 

 sea-butterflies, and to the cuttlefishes. It consists essentially of an 

 elongated ribbon-like structure, bearing hooked teeth, generally dis- 

 posed in transverse rows. This apparatus, set in action by special 

 muscles, and worked after the fashion of a chain-saw, is used to rasp 

 down the food ; whilst new growths of its substance from behind 

 serve to repair the loss caused by the friction to which it is subjected. 



