SPOROZOA, a large and most important section of the Protozoa, all the members of which are exclusively parasitic in habitat.
Sporozoa differ greatly as regards the effects which they produce upon their hosts.
Correlated with the mode of life are the two features character istic of all Sporozoa: (a) They absorb only fluid nutriment, osmotically, and so lack any organs for ingesting and digesting solid food; and (b) they reproduce by sporulation, i.e.
Further, most if not all forms of Sporozoa 'undergo sexual conjugation at some period or other of the life-cycle.
The recognition of this fact is expressed, at the present day, by the division of the Sporozoa into several well-defined orders, which are grouped in two main divisions, each containing more or less closely related forms. One of these groups consists of the Gregarines, Coccidia and Haer_aosporidia (qq.v.).
The nomenclature assigned to these two principal divisions of the Sporozoa by different writers has varied according to the particular character on which they have primarily based the arrangement.
In other words, under the heading Sporozoa, as at present used, are included two entirely independent series of Protozoan parasites; the general resemblances which these exhibit are due to convergence brought about by their specialized mode of life.