skin　of　human　beings　may　present　the　most　extraordinary　diversities　in
  colour　and　in　texture。
  So　far　as　our　present　knowledge　goes；　the　majority　of　the　structural
  varieties　to　which　allusion　is　here　made；　are　individual。　　The　ape…like
  arrangement　of　certain　muscles　which　is　occasionally　met　with*　in　the
  white　races　of　mankind；　is　not　known　to　be　more　common　among　Negroes　or
  Australians：　nor　because　the　brain　of　the　Hottentot　Venus　was　found　to
  be　smoother；　to　have　its　convolutions　more　symmetrically　disposed；　and
  to　be；　so　far；　more　ape…like　than　that　of　ordinary　Europeans；　are　we
  justified　in　concluding　a　like　condition　of　the　brain　to　prevail
  universally　among　the　lower　races　of　mankind；　however　probable　that
  conclusion　may　be。
  ＇footnote＇　*See　an　excellent　Essay　by　Mr。　Church　on　the
  Myology　of　the　Orang；　in　the　'Natural　History　Review'；　for
  1861。
  We　are；　in　fact；　sadly　wanting　in　information　respecting　the　disposition
  of　the　soft　and　destructible　organs　of　every　Race　of　Mankind　but　our
  own；　and　even　of　the　skeleton；　our　Museums　are　lamentably　deficient　in
  every　part　but　the　cranium。　　Skulls　enough　there　are；　and　since　the
  time　when　Blumenbach　and　Camper　first　called　attention　to　the　marked　and
  singular　differences　which　they　exhibit；　skull　collecting　and　skull
  measuring　has　been　a　zealously　pursued　branch　of　Natural　History；　and
  the　results　obtained　have　been　arranged　and　classified　by　various
  writers；　among　whom　the　late　active　and　able　Retzius　must　always　be　the
  first　named。
  Human　skulls　have　been　found　to　differ　from　one　another；　not　merely　in
  their　absolute　size　and　in　the　absolute　capacity　of　the　brain　case；　but
  in　the　proportions　which　the　diameters　of　the　latter　bear　to　one
  another；　in　the　relative　size　of　the　bones　of　the　face　（and　more
  particularly　of　the　jaws　and　teeth）　as　compared　with　those　of　the
  skull；　in　the　degree　to　which　the　upper　jaw　（which　is　of　course
  followed　by　the　lower）　is　thrown　backwards　and　downwards　under　the
  fore…part　of　the　brain　case；　or　forwards　and　upward　in　front　of　and
  beyond　it。　　They　differ　further　in　the　relations　of　the　transverse
  diameter　of　the　face；　taken　through　the　cheek　bones；　to　the　transverse
  diameter　of　the　skull；　in　the　more　rounded　or　more　gable…like　form　of
  the　roof　of　the　skull；　and　in　the　degree　to　which　the　hinder　part　of
  the　skull　is　flattened　or　projects　beyond　the　ridge；　into　and　below
  which；　the　muscles　of　the　neck　are　inserted。
  In　some　skulls　the　brain　case　may　be　said　to　be　'round；'　the　extreme
  length　not　exceeding　the　extreme　breadth　by　a　greater　proportion　than
  100　to　80；　while　the　difference　may　be　much　less。*　　Men　possessing　such
  skulls　were　termed　by　Retzius　'brachycephalic；'　and　the　skull　of　a
  Calmuck；　of　which　a　front　and　side　view　（reduced　outline　copies　of　which
  are　given　in　Figure　26）　are　depicted　by　Von　Baer　in　his　excellent；
  〃Crania　selecta；〃　affords　a　very　admirable　example　of　that　kind　of
  skull。　　Other　skulls；　such　as　that　of　a　Negro　copied　in　Fig。　27　from
  Mr。　　Busk's　'Crania　typica；'　have　a　very　different；　greatly　elongated
  form；　and　may　be　termed　'oblong。'　　In　this　skull　the　extreme　length　is
  to　the　extreme　breadth　as　100　to　not　more　than　67；　and　the　transverse
  diameter　of　the　human　skull　may　fall　below　even　this　proportion。
  People　having　such　skulls　were　called　by　Retzius　'dolichocephalic。'
  ＇footnote＇　*In　no　normal　human　skull　does　the　breadth　of　the
  brain…case　exceed　its　length。
  The　most　cursory　glance　at　the　side　views　of　these　two　skulls　will
  suffice　to　prove　that　they　differ；　in　another　respect；　to　a　very
  striking　extent。　　The　profile　of　the　face　of　the　Calmuck　is　almost
  vertical；　the　facial　bones　being　thrown　downwards　and　under　the　forepart
  of　the　skull。　The　profile　of　the　face　of　the　Negro；　on　the　other　hand；
  is　singularly　inclined；　the　front　part　of　the　jaws　projecting　far
  forward　beyond　the　level　of　the　fore　part　of　the　skull。　　In　the　former
  case　the　skull　is　said　to　be　'orthognathous'　or　straight…jawed；　in　the
  latter；　it　is　called　'prognathous；'　a　term　which　has　been　rendered；
  with　more　force　than　elegance；　by　the　Saxon　equivalent；'snouty。'
  Various　methods　have　been　devised　in　order　to　express　with　some　accuracy
  the　degree　of　prognathism　or　orthognathism　of　any　given　skull；　most　of
  these　methods　being　essentially　modifications　of　that　devised　by　Peter
  Camper；　in　order　to　attain　what　he　called　the　'facial　angle。'
  But　a　little　consideration　will　show　that　any　'facial　angle'　that　has
  been　devised；　can　be　competent　to　express　the　structural　modifications
  involved　in　prognathism　and　orthognathism；　only　in　a　rough　and　general
  sort　of　way。　　For　the　lines；　the　intersection　of　which　forms　the　facial
  angle；　are　drawn　through　points　of　the　skull；　the　position　of　each　of
  which　is　modified　by　a　number　of　circumstances；　so　that　the　angle
  obtained　is　a　complex　resultant　of　all　these　circumstances；　and　is　not
  the　expression　of　any　one　definite　organic　relation　of　the　parts　of　the
  skull。
  FIG。　26。Side　and　front　views　of　the　round　and　orthognathous　skull　of　a
  Calmuck；　after　Von　Baer。　　One…third　the　natural　size。
  I　have　arrived　at　the　conviction　that　no　comparison　of　crania　is　worth
  very　much；　that　is　not　founded　upon　the　establishment　of　a　relatively
  fixed　base　line；　to　which　the　measurements；　in　all　cases；　must　be
  referred。　　Nor　do　I　think　it　is　a　very　difficult　matter　to　decide　what
  that　base　line　should　be。　　The　parts　of　the　skull；　like　those　of　the
  rest　of　the　animal　framework；　are　developed　in　succession　the　base　of
  the　skull　is　formed　before　its　sides　and　roof；　it　is　converted　into
  cartilage　earlier　and　more　completely　than　the　sides　and　roof：　　and　the
  cartilaginous　base　ossifies；　and　becomes　soldered　into　one　piece　long
  before　the　roof。　　I　conceive　then　that　the　base　of　the　skull　may　be
  demonstrated　developmentally　to　be　its　relatively　fixed　part；　the　roof
  and　sides　being　relatively　moveable。
  Fig。　27。Oblong　and　prognathous　skull　of　a　Negro；　side　and　front　views。
  One…third　of　the　natural　size。
  The　same　truth　is　exemplified　by　the　study　of　the　modifications　which
  the　skull　undergoes　in　ascending　from　the　lower　animals　up　to　man。
  FIG。　28。Longitudinal　and　vertical　sections　of　the　skulls　of　a　Beaver
  （'Castor　Canadensis'）；　a　Lemur　（'L。　Catia'）；　and　a　Baboon
  （'Cynocephalus　Papio'）；　'a　b'；　the　basicranial　axis；　'b　c'；　the
  occipital　plane；　'i　T'；　the　tentorial　plane；　'a　d'；　the　olfactory　plane；
  'f　e'；　the　basifacial　axis；　'c　b　a'；　occipital　angle；　'T　i　a'；
  tentorial　angle；　'd　a　b'；　olfactory　angle；　'e　f　b'；　cranio…facial　angle；
  'g　h'；　extreme　length　of　the　cavity　which　lodges　the　cerebral
  hemispheres　or　'cerebral　length。'　　The　length　of　the　basicranial　axis
  as　to　this　length；　or；　in　other　words；　the　proportional　length　of　the
  line　'g　h'　to　that　of　'a　b'　taken　as　100；　in　the　three　skulls；　is　as
  follows：Beaver　70　to　100；　Lemur　119　to　100；　Baboon　144　to　100。　　In　an
  adult　male　Gorilla　the　cerebral　length　is　as　170　to　the　basicranial
  axis　taken　as　100；　in　the　Negro　（Fig。　29）　as　236　to　100。　　In　the
  Constantinople　skull　（Fig。　29）　as　266　to　100。　　The　cranial　difference
  between　the　highest　Ape's　skull　and　the　lowest　Man's　is　therefore　very
  strikingly　brought　out　by　these　measurements。　　In　the　diagram　of　the
  Baboon's　skull　the　dotted　lines　'd1　d2'；　etc。；　give　the　angles　of　the
  Lemur's　and　Beaver's　skull；　as　laid　down　upon　the　basicranial　axis　of
  the　Baboon。　　The　line　'a　b'　has　the　same　length　in　each　diagram。
  In　such　a　mammal　as　a　Beaver　（Fig。　28）；　a　line　（'a　b'。）　drawn　through
  the　bones；　termed　basioccipital；　basisphenoid；　and　presphenoid；　is　very
  long　in　proportion　to　the　extreme　length　of　the　cavity　which　contains
  the　cerebral　hemispheres　（'g　h'。）。　　The　plane　of　the　occipital　foramen
  （'b　c'。）　forms　a　slightly　acute　angle　with　this　'basicranial　axis；'
  while　the　plane　of　the　tentorium　（'i　T'。）　is　inclined　at　rather　more
  than　90　degrees　to　the　'basicranial　axis'；　and　so　is　the　plane　of　the
  perforated　plate　（'a　d'。）；　by　which　the　filaments　of　the　olfactory　nerve
  leave　the　skull。　　Again；　a　line　drawn　through　the　axis　of　the　face；
  between　the　bones　called　ethmoid　and　vomerthe　〃basifacial　axis〃　（'f
  e'。）　forms　an　exceedingly　obtuse　angle；　where；　when　produced；　it　cuts
  the　'basicranial　axis。'
  If　the　angle　made　by　the　line　'b　c'。　with　'a　b'。；　be　called　the
  'occipital　angle；'　and　the　angle　made　by　the　line　'a　d'。　with　'a　b'。　be
  termed　the　'olfactory　angle；'　and　that　made　by　'i　T'。　with　'a　b'。　the
  'tentorial　angle；'　then　all　these；　in　the　mammal　in　question；　are　nearly
  right　angles；　varying　between　80　degrees　and　110　degrees。　　the　angle　'e
  f　b'。；　or　that　made　by　the　cranial　with　the　facial　axis；　and　which　may
  be　termed　the　'cranio…facial　angle；'　is　extremely　obtuse；　amounting；　in
  the　case　of　the　Beaver；　to　at　least　150　degrees。
  But　if　a　series　of　sections　of　mammalian　skulls；　intermediate　between　a
  Rodent　and　a　Man　（Fig。　28）；　be　examined；　it　will　be　found　that　in　the
  higher　crania　the　basicranial　axis　becomes　shorter　relatively　to　the
  cerebral　length；　that　the　'olfactory　angle'　and　'occipital　angle'
  become　more　obtuse；　and　that　the　'cranio…facial　angle'　becomes　more
  acute　by　the　bending　down；　as　it　w