1070 PARASITES OF PROTOZOA 



organisms, establishing five species for cytoplasmic parasites of Col- 

 lozoum, Sphaerozoum, and Myxosphaera, and a sixth species, in the 

 subgenus Solenodinium, for the intranuclear parasite of Thalassicolla 

 spumida. The dinoflagellate affinities of these organisms are shown by 

 the nuclear structure, the mode of mitosis, and the morphological char- 

 acteristics of the spores. The dinospores are reniform, constricted at the 

 equator, and have two unequal flagella in typical dinoflagellate arrange- 

 ment. 



Species of Peridinium and related dinoflagellates may be parasitized 

 by Coccid'mium, which, according to Chatton and Biecheler (1934), 

 resembles coccidia in the vegetative and multiplicative stages, whereas 

 the spores are typical of dinoflagellates. Chatton and Biecheler (1936) 

 reported having observed copulation and total fusion of spores of two 

 types in Cocc'idiniuni mesnili, and considered this to be the first obser- 

 vation of an indisputable sexual process in an authentic dinoflagellate. 



Keppen (1899) described from marine dinoflagellates {Cerat'mm 

 tripos, Cerat'mm jusus, and Ceratocorys horrida) the parasite Hydosac- 

 cus ceratH, which he considered to be a parasitic rhizopod. It is impos- 

 sible to obtain a complete understanding of the structure, life history, 

 and relationships of the organism from Keppen's account and illustra- 

 tions; but certain similarities to Cocc'id'mhim are apparent in the structure 

 and nuclear multiplication of the intracytoplasmic stages. Keppen did 

 not describe spores. As did the French authors in Coccid'mium, Keppen 

 pointed out a resemblance of Hyalosaccus to coccidia. He considered this 

 to be the same parasite as that observed by Biitschli (1885) in Cerat'ium 

 jusus. 



ZOOMASTIGOPHORA 



Chlamydomonads may be attacked by Colpodella pugnax, which is 

 more of a predator than a parasite. Cienkowsky (1865), who first de- 

 scribed it, found it on Chlamydomonas pulvisculus. Dangeard (1900a) 

 studied it mainly on C. dilli, but remarked that it would attack more or 

 less all species of the genus. He never, however, observed it on other 

 Protozoa. The free-swimming Colpodella is colorless, crescentic, about 

 12 |j in length, with a terminal flagellum. It becomes fixed to Chlamy- 

 domonas, perforates its membrane, and within a few minutes the cyto- 

 plasm begins to flow into Colpodella. The envelope of Chlamydomonas 



