304 DESCRIPTION OF [Pofygattrica. 



FAMILY XVIIL OPHRYOCERCINA. 



The animalcules of this small family have no lorica ; they 

 possess an alimentary canal, with two distinct orifices, the 

 anal one only being terminal. Although their motion is 

 rapid, vibratile organs are only perceived near the mouth, 

 but their long neck probably assists them in swimming, 

 and indeed is alone sufficient for that purpose. Perhaps, 

 remarks Ehrenberg, the body is covered with delicate 

 cilii. Ova granules are seen in all the species, and a con- 

 tractile vesicle in T. biceps. Neither self- division nor a 

 development in clusters has been observed. 



Genus CXVIII. TRACHELOCERCA. Sivan-like ani- 

 malcules. 



502. TRACHELOCERCA olor (Vibrio proteus cygnus, et 

 olor, M.) The white Trachelocerca. Body spindle- 

 shaped, neck simple, very long and flexible, dilated and 

 ciliated at the mouth. This creature (see figures 317, 

 318, 319,) creeps at the bottom of the vessel containing it, 

 and twines itself gracefully about conferva, or the roots of 

 lemna, but swims awkwardly. It elongates and contracts 

 its neck at pleasure, and is altogether an interesting sub- 

 ject for the microscope. Greatest length, l-36th; length 

 of body, 1 -280th. 



503. TRACHELOCERCA viridis. The green Trachelocerca. 

 Body spindle-shaped, neck simple, very mobile, long, 

 and dilated at the mouth, which has a ciliated lip. Found 

 amongst lemna. Length 1-1 20th; contracted, l-380th. 



504. TRACHELOCERCA biceps. The double-headed 



Trichelocerca. Body spindle-shaped, white; neck long, 



* 



forked, and having separated mouths. Length, 1 -190th. 



