THE OPALINID CILIATE INFUSORIANS. 



121 



ing granules larger than the achromatic granules of the nuclear 

 stroma. Apparently this distinction between two types of chromo- 

 somes obtains throughout the Opalinidae. (See Loewenthal, 1908, 

 also Metcalf, 1914.) Leger and Duboscq (1904, h) in their excellent 

 description of Protoopalina saturnalis figure both macrochromosomes 

 and microchromosomes (see fig. 37, /, p. 64 of this paper) but recog- 

 nize as true chromosomes only the latter. 



Fig. 87. — Zelleriella bofoxexa : o, an apparently abnormal daughter cell with 

 thbeh nuclei, a portion or the lines op insertion of the cilia are drawn ; 6, an 

 ordinaet cell; c, an ordinart cell but with shrunken nuclei; d, four cells, x 

 117 diameters ; a, b, and c, magnified 460 diameters. 



ZELLERIELLA BUFOXENA. new species. 



Type. — United States National Museum Cat. No. 16484. 



Host. — Bufo haematiticus Cope, three scant infections, two very 

 scant, from United States National Museum No. 14181 (a jar con- 

 taining many toads, each of those found infected with this Zelleriella 

 being 32 mm. long) , from Nicaragua, August 7, 1885 ; J. T. Bransf ord, 

 collector. 



Measurements of an average individual. — Length of body 0.105 

 mm. ; width of body 0.08 mm. ; thiclniess of body of 0.013 mm. ; 

 83103—23 9 



