on some fossil remains of man-第6部分

快捷操作: 按键盘上方向键 ← 或 → 可快速上下翻页 按键盘上的 Enter 键可回到本书目录页 按键盘上方向键 ↑ 可回到本页顶部! 如果本书没有阅读完，想下次继续接着阅读，可使用上方 "收藏到我的浏览器" 功能 和 "加入书签" 功能！


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　were；　of　the　facial　axis　upon　the
cranial　axis。　　At　the　same　time；　the　roof　of　the　cranium　becomes　more
and　more　arched；　to　allow　of　the　increasing　height　of　the　cerebral
hemispheres；　which　is　eminently　characteristic　of　man；　as　well　as　of
that　backward　extension；　beyond　the　cerebellum；　which　reaches　its
maximum　in　the　South　America　Monkeys。　　So　that；　at　last；　in　the　human
skull　（Fig。　29）；　the　cerebral　length　is　between　twice　and　thrice　as
great　as　the　length　of　the　basicranial　axis；　the　olfactory　plane　is　20
degrees　or　30　degrees　on　the　'under'　side　of　that　axis；　the　occipital
angle；　instead　of　being　less　than　90　degrees；　is　as　much　as　150　degrees
or　160　degrees；　the　cranio…facial　angle　may　be　90　degrees　or　less；　and
the　vertical　height　of　the　skull　may　have　a　large　proportion　to　its
length。

It　will　be　obvious；　from　an　inspection　of　the　diagrams；　that　the
basicranial　axis　is；　in　the　ascending　series　of　Mammalia；　a　relatively
fixed　line；　on　which　the　bones　of　the　sides　and　roof　of　the　cranial
cavity；　and　of　the　face；　may　be　said　to　revolve　downwards　and　forwards
or　backwards；　according　to　their　position。　　The　arc　described　by　any
one　bone　or　plane；　however；　is　not　by　any　means　always　in　proportion　to
the　arc　described　by　another。

Now　comes　the　important　question；　can　we　discern；　between　the　lowest　and
the　highest　forms　of　the　human　cranium　anything　answering；　in　however
slight　a　degree；　to　this　revolution　of　the　side　and　roof　bones　of　the
skull　upon　the　basicranial　axis　observed　upon　so　great　a　scale　in　the
mammalian　series？　　Numerous　observations　lead　me　to　believe　that　we　must
answer　this　question　in　the　affirmative。

The　diagrams　in　Figure　29　are　reduced　from　very　carefully　made　diagrams
of　sections　of　four　skulls；　two　round　and　orthognathous；　two　long　and
prognathous；　taken　longitudinally　and　vertically；　through　the　middle。
The　sectional　diagrams　have　then　been　superimposed；　in　such　a　manner；
that　the　basal　axes　of　the　skulls　coincide　by　their　anterior　ends；　and
in　their　direction。　The　deviations　of　the　rest　of　the　contours　（which
represent　the　interior　of　the　skulls　only）　show　the　differences　of　the
skulls　from　one　another；　when　these　axes　are　regarded　as　relatively
fixed　lines。

The　dark　contours　are　those　of　an　Australian　and　of　a　Negro　skull：　the
light　contours　are　those　of　a　Tartar　skull；　in　the　Museum　of　the　Royal
College　of　Surgeons；　and　of　a　well　developed　round　skull　from　a
cemetery　in　Constantinople；　of　uncertain　race；　in　my　own　possession。

It　appears；　at　once；　from　these　views；　that　the　prognathous　skulls；　so
far　as　their　jaws　are　concerned；　do　really　differ　from　the
orthognathous　in　much　the　same　way　as；　though　to　a　far　less　degree
than；　the　skulls　of　the　lower　mammals　differ　from　those　of　Man。
Furthermore；　the　plane　of　the　occipital　foramen　（'b　c'）　forms　a
somewhat　smaller　angle　with　the　axis　in　these　particular　prognathous
skulls　than　in　the　orthognathous；　and　the　like　may　be　slightly　true　of
the　perforated　plate　of　the　ethmoidthough　this　point　is　not　so
clear。　　But　it　is　singular　to　remark　that；　in　another　respect；　the
prognathous　skulls　are　less　ape…like　than　the　orthognathous；　the
cerebral　cavity　projecting　decidedly　more　beyond　the　anterior　end　of　the
axis　in　the　prognathous；　than　in　the　orthognathous；　skulls。

It　will　be　observed　that　these　diagrams　reveal　an　immense　range　of
variation　in　the　capacity　and　relative　proportion　to　the　cranial　axis；
of　the　different　regions　of　the　cavity　which　contains　the　brain；　in　the
different　skulls。　　Nor　is　the　difference　in　the　extent　to　which　the
cerebral　overlaps　the　cerebellar　cavity　less　singular。　　A　round　skull
（Fig。　29；　'Const'。）　may　have　a　greater　posterior　cerebral　projection
than　a　long　one　（Fig。　29；　'Negro'）。

Until　human　crania　have　been　largely　worked　out　in　a　manner　similar　to
that　here　suggesteduntil　it　shall　be　an　opprobrium　to　an　ethnological
collection　to　possess　a　single　skull　which　is　not　bisected
longitudinallyuntil　the　angles　and　measurements　here　mentioned；
together　with　a　number　of　others　of　which　I　cannot　speak　in　this　place；
are　determined；　and　tabulated　with　reference　to　the　basicranial　axis　as
unity；　for　large　numbers　of　skulls　of　the　different　races　of　Mankind；　I
do　not　think　we　shall　have　any　very　safe　basis　for　that　ethnological
craniology　which　aspires　to　give　the　anatomical　characters　of　the　crania
of　the　different　Races　of　Mankind。

At　present；　I　believe　that　the　general　outlines　of　what　may　be　safely
said　upon　that　subject　may　be　summed　up　in　a　very　few　words。　　Draw　a
line　on　a　globe　from　the　Gold　Coast　in　Western　Africa　to　the　steppes　of
Tartary。　　At　the　southern　and　western　end　of　that　line　there　live　the
most　dolichocephalic；　prognathous；　curly…haired；　dark…skinned　of
menthe　true　Negroes。　　At　the　northern　and　eastern　end　of　the　same
line　there　live　the　most　brachycephalic；　orthognathous；
straight…haired；　yellow…skinned　of　menthe　Tartars　and　Calmucks。　　The
two　ends　of　this　imaginary　line　are　indeed；　so　to　speak；　ethnological
antipodes。　　A　line　drawn　at　right　angles；　or　nearly　so；　to　this　polar
line　through　Europe　and　Southern　Asia　to　Hindostan；　would　give　us　a
sort　of　equator；　around　which　round…headed；　oval…headed；　and
oblong…headed；　prognathous　and　orthognathous；　fair　and　dark　racesbut
none　possessing　the　excessively　marked　characters　of　Calmuck　or
Negrogroup　themselves。

FIG。29。Sections　of　orthognathous　（light　contour）　and　prognathous　（dark
contour）　skulls；　one…third　of　the　natural　size。　　'a　b'；　Basicranial
axis；　'b　c；　b1　c1'；　plane　of　the　occipital　foramen；　'd　d1'；　hinder　end
of　the　palatine　bone；　'e　e1'；　front　end　of　the　upper　jaw；　'T　T1'；
insertion　of　the　tentorium。

It　is　worthy　of　notice　that　the　regions　of　the　antipodal　races　are
antipodal　in　climate；　the　greatest　contrast　the　world　affords；　perhaps；
being　that　between　the　damp；　hot；　steaming；　alluvial　coast　plains　of
the　West　Coast　of　Africa　and　the　arid；　elevated　steppes　and　plateaux　of
Central　Asia；　bitterly　cold　in　winter；　and　as　far　from　the　sea　as　any
part　of　the　world　can　be。

From　Cen