STRUCTURAL MODIFICATIONS OF PROTOZOAX PARASITES 177 



lodgement in the cell nucleus; such caryozoic forms are only specially 

 adapted cytozoict\-pes,but their habitat is always the same [Cyclospora 

 caryoUjiica, Xvcleophaga amebea, and in part Cytorydes variolcE, and 

 others); others, finally, are hematozoic, living in the blood (tr\-pano- 

 soma. Plasmodium, hemoproteus, etc.). In many cases there mav 

 be modifications of these modes of life, or combinations of two or 

 more. Thus, plasmodium may be hematozoic, cytozoic, enterozoic, 

 and coelozoic during some period of its life history in the mosquito or in 

 the blood, and the terms are too indefinite to be employed in anv way 

 save for purposes of description. In many cases, as, for example, in 

 gregarines, the young phases are cytozoic, the adult coelozoic or entero- 



FiG. 73 



Pyxinia mobiuszi, from Luhe. (After Lfeger and Dubosq.) 



zoic, and in such cases the young forms may have special organs 

 serving for attachment or for feeding, and as they grow to maturity 

 such processes may remain in the host cell, serving for attachment, or 

 as haustoria for the absorption of nutriment. Sometimes these are 

 great prolongations at one end of the cell, as in Pyxinia mubiuszi 

 (Fig. 7'S); again, many such processes may be present, as in Pfrro- 

 cephalus (jinrdi, or in ophryocystis (Fig. NO). When the organism is 

 .se.xually mature or ready for reproduction the attaciiing processes are 

 discarded and left behind in the epithelial cell of the host, while the 

 freed parasite lies in the lumen of the organ. Such attached gregarines 

 arc known as ccphalnnia, and the detached forms as s'poronf.s. The 

 cephalonts may be variously ornamented, according as the attaching 

 12 



