" 396 CLI BOREALIS. HETEROPODA. 



When still further magnified, these distinct points are evidently 

 peculiar organs, arranged with great regularity, so as to give a 

 speckled appearance to the whole of the conical appendage; and 

 their number, at a rough guess, may be estimated to be about 

 3000 on each. When very minutely examined, every one of 

 these specks is seen to consist of a transparent cylinder, not 

 unlike the cell of a polype, and containing within its cavity 

 about twenty sucking- discs, mounted upon stalks, by which they 

 can be made to project beyond the edge of their sheath, so as to 

 apply themselves to their prey. Thus, therefore, the head cf one 

 Clio will bear about (3000x20x6) 360,000 of these micro- 

 scopic suckers ; an apparatus for prehension, which is, perhaps, 

 unparalleled in the whole animal kingdom. In this manner, 

 these active little animals are enabled to seize and hold their 

 minute prey ; and their mouths are furnished with efficient 

 instruments for reducing it. The jaws, which are placed laterally, 

 as in the Articulata, are furnished with long sharp comb-like 

 projections or teeth ; and the tongue is beset with a vast number 

 of sharp spiny booklets, curved backwards. Besides the prehen- 

 sile appendages just mentioned, two sensory tentacula are capable 

 of being put forth, for the purpose of feeling for the food. The 

 Clio possesses eyes, which, though extremely minute, have a 

 very complete organisation ; and altogether its structure com- 

 pletely corresponds with what has been already remarked hi 

 regard to the character of the Class, as the Molluscous represen- 

 tative of Birds and Insects. 



1013. The Clio may be taken as the type of the shell-less Sec- 

 tion of the Class, the members of which, from the nakedness of 

 of their bodies, have been denominated GYMNOSOMATA. Of the 

 THECOSOMATA, or shelled Section, the Hyalcea (Fig. 684) is a 

 good example. The shells of all these beautiful little creatures 

 are of a most delicate glassy texture ; their shape being usually 

 pyramidal, although in many cases prominent angles project from 

 different parts of their surface. In other species, however, the 

 shell acquires a more or less spiral structure ; as in the Limaci- 

 na, the shell of which resembles that of the Nautilus in its form ; 

 and the Spirialis, in which the shell forms a delicate pointed 

 spire, and the aperture is closed by a little operculurn. 



