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THH OPALIXID CILIATE INFI'SORIANS. 257 



four, rarely more, rounded masses of dense eliromatin lyin<f npon 

 the inner surface of the nuclear membrane. These clumps of chro- 

 matin are thrown out into the cytoplasm and are there absorbed. 

 They are the bodies which Neresheimer has re<iar(led as equivalent 

 to polar bodies, but this interpretation seems incompatable with the 

 irre«>fular number of such bodies (one to four or more) which I 

 have found. 



Phenomena of nuclear de^jeneratioii are present in some of tlie 

 material used in the studies for the present pajjer. but they seem to 

 me patholo<rical. 



Ixiwenthal (1908) finds that the chromatin spheres-^ in the cysts 

 stain clear blue with Giemsa's solution, while the larjjer of the 

 granules in the nuclei stain red. With methyl j^reen in weak acetic 

 acid the spheres stain <rreen. Treated with acetic acid the spheres be- 

 come hi<i:hly refractive; then, if ammonia be added they become invis- 

 ible but are not dissolved. From these observations Lowenthal con- 

 cludes that the spheres are chromatin, but of a different nature from 

 the chromatin granules. The former he calls cyanochromatin, on 

 the basis of their reaction to Giemsa's stain, and th^ latter erythro- 

 chromatin. The cyanochromatin he regards as corresponding to 

 Schaudinn's somatic chromatin, the erythrochromatin he compares 

 to reproductive chromatin. 



Leger and Duboscq (1904. h. III) distinguish between the super- 

 ficial plates and bands of chromatin in the nuclei of Pvotoo})alina 

 saturnallii^ and other more central chromatin granules which during 

 mitosis become arranged in lines to form chromosomes. Only these 

 granular chromosomes are regarded by Leger and Duboscq as true 

 chromosomes. 



The sexual phases of the life cycle have not been studied with the 

 two classes of chromatin in mind, and we can not say with positive- 

 ness to what portions of the ordinary vegetative nucleus each corre- 

 sponds, but from my former studies of Frofoopalina it seems clear 

 that in P. intest'malis and P. eaudata the chromatin spherules in 

 the cysts are derived from the macrochromosomes. while the larger 

 of the granules in the nuclei of the cysts are the microchromosome 

 granules. These phenomena need restudy with close scrutiny of the 

 relations to the two types of chromatin, but. if the relations stated 

 in the last sentence be correct, then most if not all of the macrochro- 

 mosome material is thrown out of the nuclei and is absorbed into the 

 cytoplasm before conjugation in Opalinidae. just as the macronucleus 

 of Euciliata is absorbed at a corresponding time. This indicates 

 that the macrochromatin in the Opalinidae is metabolic, is tropho- 

 chromatin, while the granular chromatin is reproductive, is idio- 

 chromatin. Eiacli ordinary nucleus of an Opalinid is then a com- 



"^ These are really disks, not spheres. 



