120 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



M easure7nents of an average individual with resting nuclei. — 

 Length of body, 0.18 mm. ; width of body, 0,113 mm. ; thickness of 

 body, 0.032 mm. ; diameter of nucleus, 0.0278 mm. ; diameter of endo- 

 spherule, 0.00225 mm.; cilia line interval, anterior 0.002 mm., mid- 

 dle 0.0034 mm., posterior 0.00375 mm. Ten macrochromosomes, 

 microchromosomes ten. 



This is a much larger form than Bezzenberger's Z. macronu- 

 cleata and it seems to have fewer macrochromosomes, judging from 

 Bezzenberger's figures. It seems, however, a closely related species. 

 Eaff's Z. hinudeata is also a similar form. A more detailed study 



Fig. 86. — Zelleriella antilliensis, a .series op nuclei : a, a pair of nuclei from a 



CELL ENTERING UPON FISSION (EACH NUCLEUS IS IN A LATE ANAPHASE ; ONLY THE' 

 MACROCHKOMATIN IS DRAWN, AND THIS NOT ACCURATELY, THE NUMBER AND EXACT FORM 

 OF THE MACROCHROMOSOMES NOT BEING SHOWN) ; b, THE POSTERIOR ONE OF A PAIR OF 

 NUCLJDI FROM A CELL IN LONGITUDINAL FISSION, SIMILAR TO THAT SHOWN IN FiG. 84, d, 

 ONLI THE MACROCHKOMATIN BEING DRAWN ; O, ONE OP A PAIR OP NUCLfel FROM A 

 DAUGHTER CELL, IN A VERY LATH TELOPHASE, THE CHROMOSOMES BEGINNING TO BREAK 



UP. Some of tub microchromatic and achromatic granules are drawn, the two 



SORTS not being DISTINGUISHED. a AND &, MAGNIFIED 1,000 DIAMETERS ; 0, MAGNIFIED 

 2,000 DIAMETERS. 



of Raff's species, especially as to the nuclear conditions, might show 

 them to be identical, though this is improbable in view of their 

 geographical distribution and their residence in hosts which belong 

 to different families of Anura. 



Zelleriella antilliensis is the form in which attention was first 

 drawn to the double series of chromosomes, there being 10 ribbon- 

 shaped superficial macrochromosomes and 10 other more central 

 microchromosomes, each consisting of a linear series of deeply stain- 



