1054 PARASITES OF PROTOZOA 



plasm of E. nana; and in those two instances, as they stated, it prob- 

 ably was not developing there. A given species of Niicleophaga invades 

 certain hosts, and not others. Brumpt and Lavier failed to find it in 

 E. dispar, which was associated with heavily parasitized E. nana. Many 

 related species of devescovinids, however, contain what is probably the 

 same species; although there is more than one species of Nucleophaga in 

 that group of flagellates. 



In the recent review of studies on Nucleophaga by Lavier (1935b), 

 it was noted that life-history accounts indicate two modes of develop- 

 ment. One is in agreement with the life cycle of Sphaerita, as outlined 

 above. A thallus enlarges and its nuclei multiply, it is converted 

 into a sporangium, and a spore forms around each nucleus (Dangeard, 

 1895; Penard, 1905b; Mercier, 1907, 1910; Mattes, 1924; Lavier, 

 1935b). Nucleophaga of Endamoeha disparata (Fig. 218B-E) is con- 

 sidered to have this type of life history (Kirby, 1927). In the second 

 type there is no multinucleate structure, and no sporangial membrane, 

 the individual invading parasite (Fig. 218G-J) multiplying repeatedly 

 within the nucleus by division (Epstein, 1922; Brug, 1926; Brumpt and 

 Lavier, 1935a). This is the type of reproduction, evidently, in the nu- 

 clear parasite of Entamoeba cHelli, according to Sassuchin (1931); and 

 probably such a parasite would not seem to differ essentially from 

 Caryococcus (Dangeard, 1902). It is not conceivable that there should 

 be such fundamentally different types of development in members of 

 the same genus. Either the latter type is nothing but a misinterpretation 

 of the ordinary chytrid life history, because of failure to see the cytoplasm 

 of the parasite, or the parasite is not Nucleophaga. The figures of 

 Nucleophaga supposed to show this second type of reproduction do not 

 differ essentially from the other accounts — it is probably a matter of 

 differing interpretations of what is actually one form of development. 

 The similarity to Sphaerita appears to be too great to separate Nucleo- 

 phaga distantly from that genus; but the relationship of Caryococcus to 

 this needs further investigation. 



In its early phases, in any event, Nucleophaga appears as a group 

 of granules in the interior of the nucleus, occupying a limited area, 

 whereas the nuclear structure elsewhere is essentially unchanged. This 

 group of granules presumably, though it cannot always be ascertained 

 with certainty, represents the nuclei of a thallus. Nucleophaga amoebae, 



