TRACHELTUS. 55 



respiration and circulation, although some naturalists 

 entertain a different opinion. 



The genus Paramecium is now confined to those 

 creatures which exhibit rows of longitudinal cilia 

 of uniform length, Avhich are destitute of hooks, 

 styles, or other organs of motion other than cilia, 

 which have a lateral mouth, and no eye-spots. Their 

 mode of increase is by division, which may be easily 

 observed. 



Another of the treasures from the pond was a 

 species of Trachelius^ or long-necked ciliated ani- 

 malcule, which kept darting in and out of a slimy 

 den, attached to the leaf of a water-plant. The 

 body was stout and fish-shaped, the tail blunt, and 

 the neck furnished with long conspicuous cilia, 

 which enabled the advancinpj and retreatinsj move- 

 ments to l)e made with great rapidity. The motions 

 of this creature exhibit more appearance of purpose 

 and design than is common with animalcules, but 

 in proportion as these observations are prolonged, 

 the student will be impressed with the difficulty 

 of assuming that anything like a reasoning faculty 

 and volition, is proved by movements that bear some 

 resembhmce to those of higher animals, whose cere- 

 bral capacities are beyond a doubt. It is, however, 

 ahnost impossible to witness motions which are 

 neither constant nor periodic, without fancying them 

 to be dictated by some sort of intelligence. We 



