AND THE LOWER ANIMALS. 191 



applied to the Infusoria as well as to other animals. 

 Consequently the Trichodas, like other species, can 

 only be definitively regarded as perfect animals when 

 the existence of these attributes has been proved 

 in them.* 



Notwithstanding that uncertainty which time and 

 study will eventually do away with, science is in pos- 

 session of facts enough to prove that true metamor- 

 phoses, stages of transformation, and the various 

 phenomena of geneagenesis occur among the Infusoria. 

 The first are exceedingly simple. Let us, for example, 

 borrow from Messrs. Claparede and Lachmann's 

 work, the history of those presented by the Vorticella 

 tuberosa of Mtiller (Podoplirya quadripartita of Clapa- 

 rede and Lachmann), one of the most beautiful species 

 of the Acinetinean group. 



This Vorticella or Podophrya is a stationary being. 

 Its body is like a quadrangular pyramid, with very 

 rounded edges. The summit is prolonged into a 

 cartilaginous stalk, twice as long as the body, and 

 is attached to some adjacent body. At each of the 

 basal angles of this pyramid is a sort of papilla, from 

 which spring several filaments, which apparently 

 terminate in small button-like processes. These fila- 

 ments are really at the same time mouths and arms, 

 and are always extended in a radiate manner. Some- 

 times if a far larger and more powerful Infusorian 

 passes in the neighbourhood of this creature, it is 

 instantly seized, entangled in the filaments, which 

 then appear to become solid, and the terminal button- 



* I am quite aware that, in thus expressing myself, I am asking 

 for a revision of almost the entire class. But in these times 

 i ally, science should not recoil from such an undertaking. 



