268 
While  the  formation  of  the  rounded  forms  may  be  traced,  the 
reverse  process,  development  into  flagellated  parasites,  may  also  be 
seen  from  bodies  very  similar  to  Leishmania.  The  flagellum  appears 
first  as  a  comparatively  short  structure,  and  gradually  increases  in 
length,  the  body  of  the  trypanosome  becoming  stretched  out  at  the 
same  time  to  assume  the  more  ordinary  character. 
Division  was  seen  in  organisms  of  the  broad  type  alone 
Ordinary  simple  fission  is  the  commonest,  but  instances  occur  in 
which  a  triple  division  is  present. 
Many  gradations  between  the  long  and  broad  forms  are  present; 
probably  immature  specimens  of  these  types.  The  appearances  of 
all  the  forms  agree  with  the  description  of  T rypanosoma  grayi,  Novy, 
and  to  this  category  we  would  refer  the  parasites  we  have  seen  in 
Glossina  palpalis.  No  forms  recalling  T.  tullochi  were  observed. 
VII.  MORPHOLOGY  OF  FORMS  FOUND  IN 
GLOSSINA  MORSITANS 
A.  In  Intestine.  Fresh  examination. 
(1)  Long  filiform  forms,  of  approximately  the  same  width 
throughout  the  greater  part  of  the  body,  but  tapering  gradually 
towards  the  flagellar  extremity. 
(2)  ‘  Beaked  ’  forms,  with  a  narrow  posterior  portion,  succeeded 
by  a  more  or  less  oval  central  mass,  and  then  tapering  gently  towards 
the  anterior  end. 
(3)  Blunt  or  clubbed  forms,  with  a  rounded  posterior  portion,  which 
is  the  widest  part  of  the  body. 
(4)  Regularly  oval  or  ovoid  forms,  with  a  flagellum  apparently 
devoid  of  any  undulating  membrane,  projecting  from  the  narrow 
pole. 
(5)  Motionless  oval  or  rounded  forms  devoid  of  flagellum. 
The  first  four  varieties  are  motile.  The  ‘  beaked  ’  forms  are  rather 
peculiar,  in  that  the  posterior  and  bulbar  portions  always  remain  quite 
rigid,  while  the  anterior  portion  is  vibratile.  This  is  explained  by 
the  position  of  the  blepharoplast  close  to,  and  ordinarily  in  front  of 
the  nucleus,  which  lies  in  the  expanded  middle  part  of  the  parasite. 
