THE PAST AND PRESENT OF CUTTLE-FISHES. 763 



It is thus the pearly nautilus floats under certain, circumstances on 

 the surface of the water. The argonaut (Fig. 4), credited in poetry 

 and fiction with this power, never floats on the surface, as was of old 

 believed. It is simply a mundane cuttle-fish, whose two expanded 

 arms are never used as sails, after the popularly supposed fashion, but 

 are employed solely to secrete and attach to the body the false shell 

 (Fig. 4, a) with which it is provided. 



Among the two hundred odd living two-gilled cuttle-fishes, consid- 

 erable diversity of external form may be seen ; but the general type 



Fig. 5. Shells of Fossil Cuttle-fishes. 1, Turrilites ; 2, Baculites ; 3. Hamites ; 4, Scaphites. 



already described is at the same time closely adhered to ; and save in 

 the case of the paper nautilus or argonaut, in which the characteristic 

 shape of body is concealed by the shell, the cuttle-fish characters are 

 readily apparent. The shell of the paper nautilus (Fig. 4, a) is termed 

 " false " or " pedal," because it is not formed by the mantle, as all 

 true shells are, but by the two expanded arms, as already mentioned. 

 In its homology it therefore coincides with foot-secretions (such as 

 the "beard" of the mussel), and not with the shells of its neighbors. 

 The female argonaut alone possesses a " shell," the male (Fig. 4, c) 

 being a diminutive creature, measuring only an inch or so in length. 

 It is in the ranks of the two-gilled cuttle-fishes that we discover those 

 phases of cuttle-fish life which most characteristically appeal to the 

 popular mind. Thus, many species of two-gilled cuttles are eaten and 

 considered dainties by foreign nations ; it is from this group that the 

 sepia color already mentioned is obtained ; their internal shells gave 

 us the "pounce" of long ago, and formed an article in the materia 

 medica of by-gone days ; and, lastly, it is in this group that the myth- 

 ical and the real meet in the consideration of the giant cuttle-fishes 

 which the myth and fiction of the past postulated, and which modern 

 zoolosr numbers among: its realities. 



The past history of the cuttle-fishes unites in itself a knowledge at 

 once of their present position in the animal world and of their prog- 



