CLIO BOREALIS. HETEROPODA. 359 



W r hen 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 of 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 in 

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

 tative of Birds and Insects. 



I OF THE CLASS OF HETEROPODA. 



901. The Mollusks of this class (which has been generally 

 considered as an Order of the Gasteropoda, but of which late 

 researches appear to require the removal to its present position) 

 ire distinguished from all others by the structure and position 

 )f the foot. This, instead of forming a horizontal disc more or 

 ess flattened, is compressed, so as to constitute a vertical mus- 



