1092 PARASITES OF PROTOZOA 



large nuclei. No cell boundaries were seen, and the nuclei varied in 

 size. The outer layer of the body does not have an epithelial structure; 

 and perhaps the evidence for the nuclear nature of the inclusions is 

 inconclusive. 



The parasites can easily be induced to leave the host. Borgert found 

 it sufficient to put Sticholonche in a small amount of water on a slide, 

 when escape was apparently stimulated by the increase in salinity and 

 possibly in temperature. At the beginning of the transformation to the 

 free stage, the tip of the conical part breaks through the surrounding 

 sphere, and cilia appear and become active. The entire body, having 

 become everted, emerges and swims actively in the water. Its form is 

 elongated and more or less cylindrical, and it possesses a spiral furrow 

 in which arise abundant small cilia (Fig. 226C). In the interior is a 

 cavity, larger in younger specimens, reduced to a tubular form in older 

 ones, which sometimes is open at the posterior end of the body. 



Amoehophrya acanthometrae was found in four acanthometrids by 

 Hertwig, in two others by Haeckel, and in a seventh species by Borgert. 

 Borgert stated the probability that the parasite will be found to occur 

 in all acanthometrids the skeletal structure of which permits. He observed 

 it only in uninucleate phases of the host. In 1895 at Naples, after 

 Amoebophrya disappeared from Sticholonche, parasites were found re- 

 peatedly in acanthometrids. 



Unlike the other species, A. acanthometrae occurs within the central 

 capsule. According to Borgert, it encloses the nucleus of the radiolarian; 

 but this fact does not discommode the latter. Nuclei are extraordinarily 

 small (up to 1 to 2 |j), and were not observed at all in some, especially 

 young, specimens. Emergence of the free phase, which is so easy to 

 observe in A. sticholonchae, happens only occasionally. Apparently the 

 nucleus of the host is removed in this process. The free form has a 

 plumper figure than that from Sticholonche, and the cilia are better 

 developed. 



There remain to be considered the groups of small spherules which 

 occur usually in specimens of Sticholonche without Amoebophrya, 

 though sometimes, contrary to the opinion of Fol (1883), the two are 

 found in a single host. Younger stages, according to Borgert, consist of 

 a spherical protoplasmic mass with a few spherical nuclei. A great 

 number of small nuclei result from division of these. Eventually these 

 nuclei become the center of vesicles, which become free in the host 



