10 SHELL GALLERY. 



Nautilus, or Aryonauta, is too well known to require any descrip- 

 tion. Unlike the shells of other Mollusca, it is not attached to 

 the animal by a special muscle, but is held on to the body by two 

 of the arms, which are dilated and specially adapted for this purpose. 

 Only the female Argonaut is provided with a shell, the male being 

 shell-less and a much smaller creature. The Argonaut-shell is 

 therefore not a true shell, but simply a receptacle for the ova, serving 

 at the same time for the protection of the parent. 



The species of Octopus are found on the shores of almost all tem- 

 perate and tropical seas; they do not attain to a large size, and are 

 without the internal shell or " bone " which is found in the mantle 

 of many Cephalopods. That of the Cuttlefish or Sepia (fig. 2 a) 

 is found in abundance on our coasts ; it is composed of numberless 

 layers of a friable calcareous substance. That of the Squid tribe is of 

 quite another character, consisting of an elongate thin horny plate, 

 and strengthened by one or more thickened ribs, in some species 

 somewhat resembling a quill-pen. Some species of this pen-bearing 

 class related to the Common Squid attain an immense size. One 

 was captured off the Irish coast in June 1875 (probably Architeuthis 

 harveyi) with the shorter arms 8 feet in length and 15 inches in 

 circumference at the base, the two tentacular arms having a total 

 length of 30 feet. The powerful beak measured about 4 inches across. 

 Thus from the tip of the tail to the end of the tentacular arms 

 this wonderful monster must have measured something like 40 

 feet in length. Other very large specimens of Architeuthis have 

 been captured on the coasts of Newfoundland and Labrador. Two 

 specimens stranded on the south coast of Newfoundland, in the 

 winter of 1870-1871, measured respectively 40 and 47 feet. 

 Another, cast ashore at Bonavista Bay in December 1873, had a 

 very stout body 14 feet long, arms 10 feet, and tentacles 24 feet 

 in length. These are only a few of the many instances of the 

 capture of gigantic Cephalopods, which occur not only in the 

 North-Atlantic Ocean, but also in tropical seas. Their appearance 

 in mid-ocean may, in some instances, have given rise to the tales of 

 '•' Sea-serpents." Specimens much smaller than those mentioned 

 above have attacked men, and pearl-fishers are in constant fear of 

 them. One of the arms of a large Squid {Architeuthis harveyi ?), 

 which is supposed to have been found off the coast of South America, 



