91 
and  aculeus  5.5,  of  aculeus  1.8;  length  of  humerus  4,  of  brachium 
4.3  ;  of  manus  and  dactyli  9.5,  of  morable  dactylus  5.4 ,  of  hank-back 
4.5;  width  of  hand  5.5,  of  brachium  2.7,  of  humerus  2.2;  sternum, 
length  from  posterior  angle  to  middle  of  anterior  border  2.2,  width 
across  posterior  angles  2,  width  in  front  1.6. 
In  the  smallest  specimen,  which  is  also  paler  in  colour,  the  manus 
is  narrower,  its  width  not  equalling  the  length  of  the  movable  dacty- 
lus (3:  3.5). 
I  suspect  that  Thoeell's  genus  Chelomachus  *)  is  not  distinct  from 
Chaerilus.  It  was  established  on  the  grounds  that  the  sternum  is  as 
wide  as  long  and  not  longer  than  wide  as  in  Chaerilus.  But  in  these 
specimens  of  variegatus  the  length  of  this  plate  only  exceeds  the  width  by 
the  merest  fraction.  Indeed  if  the  length  be  taken  along  the  middle  line 
it  is  only  equal  to  the  width  across  the  posterior  angles.  In  this  genus 
the  sternum  approaches  the  triangular  form  that  is  seen  in  the  Buthidae  ; 
and  another  curious  point  in  which  this  species  at  least  resembles 
this  family  is  the  presence  of  that  remarkable  smooth  >  shaped  area 
on  the  tergites  which  is  so  common  in  many  species  of  Buthidae. 
In  addition  to  Chelomachus ,  I  suspect  that  my  genus  Uromachus  will 
also  have  to  fall  as  synonymous  with  Chaerilus.  This  genus  was  based 
upon  specimens  exactly  agreeing  with  Chaerilus  except  in  the  strange 
shape  of  the  caudal  vesicle.  But  since  this  peculiarity  was  not  correlated 
with  other  structural  features,  I  thought  that  it  might  prove  to  be 
sexual.  And  at  the  time,  I  did  not  recollect  that  Petee's  genus. Eemis- 
corpio  presents  much  the  same  modification  of  this  segment  ;  and  since 
the  two  genera  belong  certainly  to  distinct  sub-families  and  there  is  no 
direct  affinity  between  them,  it  struck  me  that  the  probability  that 
this  character  would  prove  to  be  sexual  was  sensibly  increased.  There 
is,  however,  so  far  as  I  know,  no  direct  evidence  of  the  fact. 
6.  Chaerilus  cavernicola,  sp.  n.  (Pl.  VI,  fig.  5  —  5a). 
Three  specimens  2  adult  (?ç?  and  Ç),  and  1  young  (?cT)  from  the 
cavern  Ngalau  near  Pajacombo  in  Sumatra. 
Colour  fuscous,  variegated  with  fia  vous,  intercarinal  spaces  of  the 
tail  mostly  flavous,  keels  on  tail  and  hands  fuscous  with  flavous 
spots,  dactyli  fuscous,  fulvous  at  the  apex,  under  surface  of  trunk 
ochraceous,  of  hands  rufo-ochraceous. 
1)  Ann.  Mus.  Gen.  XXVII,  pp.  583—584. 
