﻿CRUSTACEA. 
  521 
  

  

  4, 
  Menaetliius 
  monoceros 
  (Latr.). 
  

  

  A 
  scries 
  of 
  specimens 
  of 
  both 
  sexes 
  and 
  various 
  ages 
  are 
  in 
  the 
  

   collection 
  from 
  the 
  Seychelles, 
  4-12 
  fms. 
  (No. 
  194) 
  ; 
  also 
  a 
  small 
  

   female 
  obtained 
  on 
  the 
  beach 
  at 
  Mozambique 
  (No. 
  224), 
  which 
  has 
  

   the 
  prominences 
  or 
  lobes 
  of 
  the 
  antero-lateral 
  margins 
  spiniform 
  

   and 
  acute. 
  

  

  I 
  have 
  already 
  referred 
  to 
  this 
  widely 
  distributed 
  and 
  variable 
  

   species 
  on 
  p. 
  lUO. 
  

  

  A 
  small 
  female 
  specimen, 
  which 
  has 
  unfortunately 
  lost 
  all 
  the 
  

   legs, 
  obtained 
  at 
  African 
  or 
  Eagle 
  Islands, 
  10 
  fms. 
  (No. 
  184), 
  has 
  

   the 
  rostrum 
  remarkably 
  abbreviated, 
  not 
  equalling 
  in 
  length 
  the 
  

   interocular 
  width 
  of 
  the 
  frontal 
  region 
  of 
  the 
  carapace, 
  the 
  greatest 
  

   width 
  at 
  the 
  branchial 
  regions 
  little 
  exceeding 
  the 
  width 
  at 
  the 
  

   frontal 
  region, 
  and 
  the 
  basal 
  antennal 
  joint 
  more 
  dilated 
  than 
  in 
  the 
  

   typical 
  M. 
  monoceros. 
  It 
  appears 
  to 
  merit 
  distinction 
  at 
  least 
  as 
  a 
  

   variety, 
  since 
  I 
  have 
  seen 
  no 
  specimen 
  in 
  the 
  extensive 
  Museum 
  

   series 
  which 
  closely 
  resembles 
  it, 
  but 
  I 
  refrain 
  for 
  the 
  present 
  from 
  

   designating 
  it 
  as 
  such. 
  

  

  5. 
  Stilbognathus 
  martensii. 
  (Plate 
  XLVI. 
  fig. 
  B.) 
  

  

  I 
  propose 
  thus 
  to 
  designate 
  two 
  males 
  obtained 
  at 
  Marie-Louise 
  

   Island, 
  17 
  fms. 
  (No. 
  180), 
  and 
  a 
  male 
  from 
  Providence 
  Island, 
  li) 
  

   fms. 
  (No. 
  217), 
  which, 
  although 
  having 
  the 
  ischium-joint 
  of 
  the 
  

   outer 
  maxillipcdes 
  longitudinally 
  sulcated 
  (and 
  hence 
  certainly 
  

   belonging 
  to 
  iStilbofjiiatJivs), 
  differ 
  from 
  Stilhoynatlius 
  erythraus, 
  Von 
  

   Martens*, 
  from 
  the 
  Ued 
  Sea, 
  in 
  the 
  form 
  of 
  the 
  merus-joint, 
  which 
  

   has 
  its 
  extero-distal 
  angle 
  produced 
  and 
  acute 
  as 
  in 
  Stenocionops 
  

   cervicornis, 
  and 
  which 
  further 
  differs 
  from 
  the 
  known 
  species 
  both 
  

   of 
  Stenocionops 
  and 
  iStilbogjutthus 
  in 
  having 
  the 
  notch 
  on 
  the 
  inner 
  

   margin 
  (where 
  the 
  fourth 
  joint 
  articulates 
  with 
  it) 
  provided 
  with 
  a 
  

   tooth 
  or 
  lobe 
  (see 
  fig. 
  h). 
  

  

  The 
  carapace 
  is 
  constricted 
  behind 
  the 
  orbits 
  (as 
  in 
  S. 
  cerviconiis) 
  ; 
  

   the 
  gastric, 
  cardiac, 
  and 
  front 
  of 
  the 
  branchial 
  regions 
  are 
  rather 
  

   convex 
  and 
  more 
  or 
  less 
  distinctly 
  covered 
  with 
  small 
  tubercles 
  or 
  

   granules 
  ; 
  the 
  posterior 
  margin 
  of 
  the 
  carapace 
  is 
  cristate 
  and 
  pro- 
  

   longed 
  in 
  the 
  median 
  line 
  into, 
  a 
  tooth 
  or 
  lobe. 
  The 
  spines 
  of 
  the 
  

   rostrum 
  are 
  slender 
  and 
  curved 
  at 
  first 
  outwards 
  and 
  then 
  inwards 
  

   so 
  as 
  to 
  meet 
  at 
  the 
  apices, 
  which 
  are 
  vertically 
  refiexed 
  as 
  in 
  ISte- 
  

   nocionops 
  cicrvirostm, 
  A. 
  M. 
  -Edwards. 
  There 
  is 
  a 
  rounded 
  prominence 
  

   upon 
  each 
  pterygostomian 
  region. 
  The 
  supraocular 
  spines 
  of 
  the 
  

   carapace 
  are 
  very 
  long 
  and 
  straight 
  ; 
  the 
  eye-peduncles 
  even 
  longer 
  ; 
  

   the 
  basal 
  antennal 
  joint 
  is 
  considerably 
  dilated, 
  and 
  has 
  a 
  small 
  

   spine 
  on 
  its 
  outer 
  side 
  near 
  the 
  base 
  and 
  another 
  at 
  its 
  distal 
  ex- 
  

   tremity. 
  The 
  longitudinal 
  pit 
  on 
  the 
  outer 
  surface 
  of 
  the 
  ischium- 
  

   joint 
  of 
  the 
  outer 
  maxillipcdes 
  is 
  longer 
  than 
  in 
  Stilhoynatlais 
  erij- 
  

  

  * 
  Verbandl. 
  zool.-bot. 
  Gcscllsch. 
  Wieu, 
  xvi. 
  p. 
  370, 
  \. 
  (1866). 
  

  

  