Vorticellina.] the infusoria. 271 



larger egg-shaped ones, having hairs at their point, and only 

 a Uttle round, but not vibratile, opening. The latter ones are 

 most probably parasitical bodies, the others are not. This 

 genus is not figured by Ehrenberg. 



417. Operculabia articulata {V. Opercularia, M.) 

 The articulated Opercularia is in the form of a little 

 shrub, l-6th to l-4th high, white and dichotomous. This 

 animalcule readily takes in carmine and indigo ; and 

 Ehrenberg states, he saw as many as forty-four stomach- 

 cells filled, resembling a girdle in the middle of the body. 

 The stalk is very delicately striated in a longitudinal 

 direction, and shews, at its divarications, a transverse line, 

 or joint. Found upon Dyticus marginatus. Size 1 -430th. 



Genus XCIV. Zoothamnium. The double-shaped little 

 bell Animalcules comprehend Vorticellina with a flexible 

 spiral pedicle, having an internal muscle, and becoming 

 branched, from imperfect spontaneous division. The 

 stalked corpuscles are of diff'erent shapes, and have a 

 simple lateral mouth opening. In one species, a wreath 

 of cilii, placed around the frontal region, constitutes the 

 locomotive apparatus ; and a special muscle or fibre runs 

 along the branches and stem. Artificial means are able 

 to demonstrate numerous round stomach-cells. No re- 

 productive organs have been detected; but simple and 

 comjDound self-division has been observed. 



418. Zoothamnium arbuscula ( Vorticella racemosa, M.) 

 The tree-like Zoothamnium has the branches of the little 

 tree in racemes or umbels ; the cor])uscles being white, 

 and the pedicle very thick, {^eefig. 247, which is more 

 highly magnified than 248). These beautiful little trees 

 resemble plumes of feathers, at once distinguishing them- 



