EARLY DEVELOPMENT OF GRAFFILLA. 185 



Lang, '84, next noted the aborting spindle in several polyclad 

 eggs, and figures it in the uterine egg of Thysanozoon Brocchii. 



\\ "heeler, '94, describes briefly the appearance of the uterine 

 ^pindle in the eggs of Planocera inqiiilina, a polyclad inhabiting 

 the br.iiichi.il chamber of Sycotypus canalicalalns, but does not 

 attempt to work out the details of the process. He also noted 

 the spindle in the eggs of the acoelan Polycfnvrus cuitdutn*. 



< .ardiner. '95 and '98, working on the latter specie- came to 

 tin i MM lu-ion that the aborting spindle is abnormal, ivpre-enting 

 tin- hr-t clea\ai;e spindle of eggs retained too long in the HUTU- 

 o| .in animal kept under abnormal conditions. His point does 

 not -eem to be well taken, as Surface, '07, ha- -hown in hi- work 

 on I'lniiK, ,-r<i. 



I lie la-t reference to the aborting spindle thai \\e may note 

 i- tint ot I.. \ on ( iraff, '82, in his monograph on the Khabdocielida. 

 Von (.rail, although making no reference to tin- -pindle in the 

 text. ili.uK h-ures one in the uterine eggs of .1 f>li<uio*ti>nui 

 <//. md Cyptomorpha saliens. 



In our -pei ies, (/. gemettipara, the aborting -pimlle appear- in 



the < e time before the freeing of the egg-capsule from the 



\iiellaiinm. The spindle is really anticipated Ion- belon- .ill ot 

 the \ulk i- laid down about the two eggs, as can be -> n in 1 iu. to. 

 In man\ ie-pcvts the spindle is truly remarkable. \\ t ,\ ,,\\\\ on 

 ,n ' omit ot its great size, but also for the iva^m that tie,|iieiitl\ 

 the clii-onio-onu> do not appear upon it. < >ne ot the dearest 

 cases that ha- come under my observation i- -ho\\n in 1 i-. 17. 

 Thi- i- an e-pei'ially well preserved egg, \et one can not detecl 

 the ^li^hte-t tiare of chromosomes in the cell. HOU.-MT, it i- 

 probable that the chromatin is represented by some of the central 

 -pimlle liber-, \\hich are (juite thick but do not take the -tain 

 \\ell. Thi- i- most certainly the case in some eggs in which MT\ 

 delicate i hroinatin threads among the spindle fibers can with 

 (lillicnlty be made out. 



- -int-iime- the chromatin is in the form of chromo-<>me.-, which 

 ho\\c\ er are not located on the spindle. In Fii;. I S is -ho\\ n -nch 

 a case. Hen- the large conspicuou- ^pindle i- it-ill" free from 

 chromatin, but among the astral ra\> of one end are four chro- 

 mo-omr-, \\ hich are of intcre-t not onh bei ause of their pi-i-uliar 



