300 TlMEHRI. 
To the philosopher and the biological student, 
more especially, the contemplation of the structure 
and the relations of the Zoophytes is one that teems 
with absorbing interest, since the typical stage of 
development that is here permanent, is a transitory stage 
in the development of all the higher animals, and presents 
us with the connecting link between the primitive uni- 
cellular condition of the lowest forms and the complex 
aggregates represented by the highest. As a unit, so to 
speak, in the evolution of the higher forms, the Zoophytic 
plan or type of organisation, is one that is most easily 
recognised, and, being of universal occurrence, one that 
is of material importance. 
The term " Zoophyte" is still often applied in a 
very vague and unsatisfactory manner to include 
not only the animals thus properly designated, but 
also a very large assemblage of more lowly organ- 
ised forms such as the Animalcules (Protozoa), and 
of more highly organised beings such as minute mol- 
luscs, worms, and other creatures, besides many 
undoubted plant forms. Scarcely more than a century 
ago, these forms, apparently destitute of the manifes- 
tations of life characteristic of the higher animals, were 
regarded as of a distinctly vegetable nature with animal 
affinities, which caused them to be regarded as inter- 
mediate between the two kingdoms ; and the history 
of the patient and elaborate researches by which their 
entire animality was brought to light, and of the persis- 
tent and violent opposition with which such a conclusion 
was met by the leading scientists of the time, forms one 
of the most interesting and suggestive chapters of 
attempted scientific dogmatism. 
