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532
HUGGINS
•T ^L.,Ossification
in theNestling
HouseWren
OSSIFICATION
IN
THE
NESTLING
HOUSE
['Auk
LOct.
WREN
BY RUSSELL A. HUGGINS, SARA E. HUGGINS,
ISABELLE
H.
HELLWIG
AND
GERI-IARD
DEUTSGHLANDER
As a necessary
preliminaryto work on the effectsof certainhormones
on the time relationsof ossificationand relative growth in the House
Wren (Troglodytesa•don a•'don),it was essentialto determinethis
relationshipin normalindividuals. This paperin a qualitativemanner discusses
briefly the first appearance,fusion and articulation of
bonesin the skeletonsof normal nestling House Wrens.
At least four birds for each day in the nest were collected. The
birds were killed, the skeleton was stained with Alizarin
Red S. and
clearedby Dawson'smethodasgivenin A. B. Lee's'The Microscopist's
Vade Mecum'(Philadelphia,P. Blakeston's
Sonsand Co., 1937). There
have been numerousarticlespublishedconcerningthis method but
the authorshave been unable to discoverany extensiveuse of this
techniquefor a studyof this kind.
FORE LIMB
O day.--The humerusis a short thick bone with the endsslightly
flared. The radius is about the samelength as the ulna but thinner,
not as heavily ossified,while the endsof the ulna are more flattened
than thoseof the radius. The radiale and ulnare are not present.
In the carpometacarpus
the third metacarpalis heavierand largerthan
the fourth metacarpal;the latter is a slenderbone while the endsof
the third metacarpalare somewhatthickened. The seconddigit is
a minute bone. In the third, both of the phalangesare present,
althoughthe distal is much smallerthan the proximal. The fourth
digit is not present,nor is the secondmetacarpal. [The three fingers
of the hand are regardedasnumbers2, 3, and 4 of the primitive five.]
Third day.--Distal and proximal ends of the humerus are more
expanded. The fourth digit and the secondmetacarpalhaveappeared.
Fourth day.--Presentfor the first time is the beginning of the
tuberculum ulnare ossimetacarpi.
Fifth day.-The tuberositiesof the humerus are much more
prominent.
Seventhday.--The radial and ulnar bonesare presentfor the first
time.
Eighthday.--Thetuberculumulnareossimetacarpihasunitedwith
the proximal end of the third metacarpal. Two small centersof
ossification
have appearedcloseto the third metacarpal,and a third
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HUGGINS
ETAL.,Ossification
in theNestlingHouseWren
533
has appearedbetweenthe fourth metacarpaland the ulna. The
epiphyses
of the humerusand ulna haveappeared.
Ninth day.--In the humerusthe caputhumeri is beginningto fit
into the glenoidfossa. The fourth metacarpalhasdevelopeda slight
indentationfor articulationwith the third metacarpaland the second
metacarpalis touchingthe proximalend of the third metacarpal.
TEXT-FIGUREl.--Fore limb of nestling House Wren: I, humerus; 2, radius;
3, ulna; 4, seconddigit; 5, third metacarpal;6, fourth metacarpal;7, first phalanx
of third digit; 8, secondphalanx of third digit; 9, radiale; I0, ulnare; I1, fourth digit.
Tenth day.--The secondmetacarpalis beginningto fuse with the
preaxialsideof the proximalendof the third metacarpal.
Twelfth day.--The head of the humerus has now reached adult
proportions.The trochleaeare well formedon the humerus. The
radius articulateswith the humerusand radiale and the proximal
endisexpandedandconcave
for articulationwith the obliquetubercle.
534
HUGGINS
ETAL.,Ossification
in theNestling
HouseWren
['Auk
L Oct.
The proximal end of the ulna articulateswith the ulna tubercleof
the humerus while the distal end articulates with the radiale, ulnare
and head of the third metacarpal. The third metacarpalhas fused
with the fourth metacarpal. The third finger articulateswith the
third metacarpal. Fusion of the epiphysesof the humerusis completedand the epiphysisat the distalend of the ulna is fused.
TEXT-FIGURE2.--Hind limb of nestling House Wren: 1, femur; 2, fibula; $,
tibio-tarsus; 4, tarso-metatarsus; 5, remnant of first metatarsal; 6, first toe; 7, second
toe; 8, third toe; 9, fourth toe.
Thirteenth day.--The radius articulateswith the oblique tubercle
and with the radiale at the distal end.
The ulna articulates with the
humerus. Two new centersof ossification
haveappearedat the distal
end of the ulna.
The radiale articulates with the radius while the
ulnare is attachedto the third metacarpal. The third metacarpal
articulateswith the secondfinger, fourth metacarpal,ulnare and
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•9-aI
1942
HUGgINS
ETAL.,Ossification
in theNestling
HouseWren
535
radiale. The fourth metacarpalarticulateswith the fourth finger.
Fourteenthday.--Theradiusarticulateswith the humerusand ulna.
The
radiale
articulates
with
the radius and tuberculum
ulnare
ossi
TEXT-FIGURE
3.--Pelvicgirdle of nestlingHouseWren: 1, ilium; 2, pubis;
3, ischium; 4, acetabulum; 5, ilio-ischiac foramen.
metacarpi.The epiphysis
at the proximalendof the ulnais fused,
as are also the third and fourth metacarpals
and the ulnare. The
twocenters
appearing
on thethirteenthdayhavenowfusedwith the
ulna. Also,the second
metacarpal
articulates
with the second
digit.
536
Hu•Ns•T AL.,Ossification
in theNestling
House
Wren
['Auk
L Oct,
SI•OULDER GIRDL•
0 day.--The
scapula
isa shortstocky
bonewiththeendsexpanded.
The coracold
is approximately
of thesamesizeasthescapula
and
has about the sameamount of ossification. The claviclesare thread-
like in thickness
and arejoinedby the minuteinnerclavicle.
Firstday.--The
coracoid
bears
hook-like
processes
onitsupperend.
Thesewill be part of the glenoidœossa.
TEXT-FIGURE
4.--Skullof nestlingHouseWren; sideview.
Third day.--Three tuberosities,
which will articulatethe anterior
headof thecoracoid
withtheotherpartsof theshoulder
girdleand
humerus,
arenowpresent.
Ninthday.--The
œurcula
isalmost
touching
theendof thescapula.
A headis formingfor articulationwith the coracold. A headis also
formingon the œurcula.
Twel[th day.--Thedistalportionof the coracoidarticulates
with
thesternum
andtheproximal
endarticulates
withthescapula
to
formtheglenoidcavity.
Thirteenthday.--Thescapulaarticulates
with the humerus,coracoid and œurcula.
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•o]
•õ4•
.•
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ETAL.,Ossification
in theNestling
HouseWren
HIND
537
LIMB
0 day.--The femur, tibio-tarsus,fibula, tarso-metatarsus,
remnant
of the first metatarsal,phalangesand clawsare all present. The
three bonesthat have fused to form the metatarsusare still visibly
separatedat both endsof the bone and only partially fusedthrough
the shaft. The first phalanxof the fourth toe is moderatelyossified
but the three other phalangesare barely distinguishable.
First day.--The proximal end of the femur has begunto develop
into the caput fcmoriswhile the distal end showsthe beginningof
the condyle.
Secondday.-A smallcenterof ossification
develops
outsidethe distal
end of the tibio-tarsus.
Fourth day.--Secondsmall center of ossificationdevelopsoutside
the distal end of the tibio-tarsus.
Fifth day.--Themetatarsus
hasan indentationon its innerposterior
surface. A third center of ossificationhas developedat the distal
end of the tibio-tarsus.
Seventhday.--The cap at the proximal end of the tarso-metatarsus
is visible. The distal headof the tibio-tarsusis beginningto take form
by the fusionof the three small bonesmentionedabove. A small
sesamoidbone appearsbesidethe proximal extremityof the tarsometatarsus.
Eighth day.--Threecentersof ossification
have appearedat the
distal end of the femur and mark the beginningof the patella. A
small center of ossification has formed
near the distal end of each
of the three splintsforming the tarso-metatarsus.
Ninth day.--The three centersof ossification
that are closeto the
tarso-metatarsus
fuse to form the triple trochlearhead which articulates with the second, third and fourth toes. A center of ossification
hasdevelopedat the anteriorheadof the fibula.
Tenth day.--Thecentersof ossification
for the patellahave fused.
The center of ossification at the anterior
head of the fibula has fused
with the fibula, supplyinga surfacefor articulationwith the outer
condyleof the femur.
Twelfth day.--A small centerof ossification
has developedby the
cap at the distalend of the femur. The headof the femurnow fits
into the acetabulum. There are small ossifiedstrandsrunning from
fibula
to tibio-tarsus.
The
tibio-tarsus
articulates
with
the anterior
head of the tarso-metatarsus.The first metatarsalhas joined the
taxso-metatarsus.
The third digit articulateswith the metatarsus
and the fourth partially so.
538
HUggINS
•T AL.,Ossification
in theNestling
HouseWren
]'Auk
LOct.
Thirteenth day.--Articulationbetweenphalangesis now complete.
Fourteenth day.-Epiphysis of the femur, tibio-tarsusand tarsometatarsusjoin their respectivediaphyses.
PELVIC
GIRDLE
0 day.--Thethreebonesthat constitutethe pelvicgirdlearepresent.
The ischiumis the mostsolidlyossified;
beneaththe ilium the lumbar
vertebraeareeasilyseen,while the slenderpubisisjust distinguishable.
Secondday.--Thepubisis now clearlyseenand is approachingthe
ilium.
Third day.-The endsof the ischiumare slightlyexpanded.
Fourth day.--Theheadsof the ischiumare more expandedand a
smallheadhasformedon the anteriorend of the pubis.
Sixth day.--Fusionisbeginningbetweenthe ilium and the synsacrum.
Eighth day.--The threebonesof the pelvicgirdlehavemet to form
the acetabulum,but the only fusion apparentis betweenthe ilium
and the ischium.
Tenth day.-The ilioischiacforamenis just being formedwith the
fusionof the posteriorendsof the ischiumand the ilium.
Twelfth day.--Thepubisand the ilium havefusedat the acetabulum.
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•oI
•94•
a
HVGGXNS
•X AL.,Ossification
in theNestling
HouseWren
539
Thirteenth day.-The suturebetweenthe ilium and the synsacrum
is evidentand completefusionof the pelvicboneis accomplished.
THE
SKULL
0 day.--Theoccipitalshowsfour centersof ossification.The frontal
and parietal are presentbut very lightly ossified. There are small
processes
on the temporal for later articulation with the quadrate.
In the premaxilla, the lateral halvesare completelyfused together
and the processifrontales are present. There are three main divisionsof the maxilla and they are not yet completelyfused. The
nasal is very faintly ossifiedwhile the lacrimal is not present. The
palatine appearsto be joined to the nasal portion of the sphenoid.
The pterygoidis connectedwith the palatineand the articularfacet
is beginningto develop. The zygomais much curvedwith a slight
widening of the posteriorend (quadrato-jugal)while the jugal is
already fusedto the maxilla. The vomer is presentbut ossification
is very slight. In the quadratedevelopmenthas alreadyprogressed
toward articulation with the temporal portion of the skull. The
inferior maxilla can be seenvery faintly. In the hyoid, two small
bones are visible with their ends more heavily ossified. There are
signsof ossificationof the cornealmargin of the scleroticcoat.
Secondday.--Eyering is completebut ossification
is light.
Third day.--The four divisionsof the occipitalare still separate.
The rostrumis presenton the sphenoid. The temporalis joining
with the frontal. The lacrimal still is not present. The pterygoid
appearsto be joined anteriorlyto the posteriorend of the palatine.
The vomeris apparentlyfusedwith the rostrumof the sphenoid. In
the hyoid a third centerof ossification
hasappearedbetweenthe two
previouslymentioned. The platesof the eyesare muchmoredistinct.
Fourth day.--The ear cavityis beginningto form in the temporal.
The premaxilla has fused with the nasal. The pterygoidis fused
with the rostrumof the sphenoid. The quadrateis about ready for
articulation with quadrato-jugal. The os articulate of the inferior
maxilla is beginningto form.
Fifth day.--Thesphenoidappearsto be connected
with the quadrate
and is nearly connectedwith the lateral occipital. The quadrate
articulates
with
the os articulate
of the inferior
maxilla.
Sixth day.--There is fusion between the parietal and the lateral
occipital.
Seventh day.--Pterygoidarticulateswith the quadrate while the
quadrato-jugal
is articulatingcloselywith the quadrate.
•z• 0
HVGG•NS
ETAL.,Ossification
in theNestlingHouseWren
['Auk
L Oct.
Eighth day.--The lateral and supraoccipitalparts have fused and
the occipitalis curving around to form part of the ear cavity. The
sphenoidappearsto be joiningwith or touchingthe occipitalventrally.
The temporal and quadratearticulate. The palatine appearsto be
fusedwith the inner edgesof pterygoid. The basi-hyalof the hyoid
is present.
Ninth day.--The four partsof the occipitalare all fused. Sutures
between
the two frontals
extend
down to the nasal bone.
TrXT-F•GUnr6.--Skull of nestlingHouse Wren; ventral view.
Tenth day.-There is generalfusionbetweentemporal,lateral occipital, sphenoidand quadrate. The lacrimal is seenfor the first time.
Zygomaand jugal articulateand the inferior maxilla articulateswith
the quadrate.
Twelfth day.--The temporalis fusedwith the sphenoid. By this
time mostof the skull bonesare completelyfused.
VERTEBRAL COLU•VIN,RIBS AND STERNUM
0 day.--In the cervicalregion there are thirteen small vertebrae,
eachhavingthree centersof ossification:
the right and left halvesof
the neural arch and the centrum. The vertebraedo not yet articulate
with
each other.
The
atlas and axis are not as well formed
as the
other cervicalvertebrae. The seventhoracicvertebraeare larger and
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•9]
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HutchesETAL.,Ossification
in the NestlingHouseWren
moreheavilyossified
but in extentof developmentare like the cervical.
Eight ribs are presentbut unattached. The vertebral end of all but
the first rib is slightlydivided into the capitulumand tuberculum.
In four of the specimens
the firstrib is difficultto see;in two others,
TEXT-FIi•URE
7.--Sternum of nestling House Wren: 1, sternal ribs; 2, first ossification centersof body of the sternum;3, keel or sternal crest;4, costalprocess;
5, xiphisternal process.
it is well formed. No ossifiedsternumis present. The lumbar and
sacralvertebraeare barely visible. In most of the specimens
it was
impossibleto count the coccygeal
vertebraeas ossification
was not
advancedenough.
Secondday.--The pygostyleis present. It is not possibleto distinguish all the coccygeal
vertebrae.
542
HVGGZNS
ZTAL.,Ossification
in theNestlingHouseWren
[Auk
LOct.
Third day.--The processes
oœthe thoracicvertebraeare developing
and transverse
processes
on the last four sacralvertebraeare present.
Fourth day.--?rocesses
of the cervical vertebrae are developing.
The zyõapophyses
are beginningto developasseparatecentersin the
cervicalregion. In the thoracicregion fusion of the centra with the
transverseprocesseshas taken place. The coccyõealsare fused
ventrally.
Fifth day.--In the cervicalregion the neural arch and the centrum
are fusedventrally at each side. The atlas is not yet fusedon the
ventral sidebut is on the dorsalside. The last thoracicis beginning
to unite
with
the first lumbar
vertebra.
A center
of ossification
is
presenton eachsideoœthe sternumand very light ossification
is present in the keel. The lumbar and sacralvertebraeare fusingtogether.
Yusion is beginningbetweenthe first coccyõealand the last sacral
vertebra.
Sixth day.--The atlas is articulatingwith the axis and the axis is
articulating with the next cervical vertebra. Yive new centersof
ossificationhave appearedon eachside oœthe sternum. Many oœthe
lumbar
and sacral vertebrae
are œused.
Seventhday.--The processes
of the cervicalvertebraehave united
with the vertebrae. The atlasis articulatingwith the singlecondyle
of the occipital. All the lumbo-sacralvertebrae are fused. The
sternumhas developedanotherlarge centeroœossificationin the keel.
Eighth day.--Yusionof someoœthe thoracicvertebraehas occurred.
The transverseprocesses
are touching the dorsal end of the ribs.
Three of the ribs have developeduncinateprocesses.Another paired
centerof ossification
has appearedin the sternum.
Ninth day.--The fusionof the thoracicvertebraeis still incomplete.
Another rib has developedthe uncinateprocess. In the lumbar and
sacralvertebraesmall processes
are being œormeddorsally. Yusion
of the three bonesthat form the sternumis beginning.
Te•th day.--Yusionoœthe sternumis nearly complete.
Twelfth day.--The uncinateprocesses
havejoined the ribs and there
is a general œusionof all vertebrae.
Thirteenth day.-In the dorsal region the superior processes
are
articulatingwith the small part oœthe rib articulars.
SUMMARY
Ossificationof all the boneshasbegunin the newly hatchedw•ens
with the exceptionof the secondmetacarpal,fourth digit, radiale,
ulnare, eye ring, lacrimal, uncinate processes
of the ribs, pygostyle
and
sternum.
Vol.
59]
1942
.s
HUGGINS
•? AL.,Ossification
in the NestlingHouseWren
5z}3
Of these,the pygostyleand the platesof the cornealmarginof the
sclerotictunic appearon the secondday, the secondmetacarpaland
the fourth digit on the third day, the radiale and ulnare on the seventh.
Uncinateprocesses
begin to developon someof the ribs on the eighth
day and the lacrimal beginson the tenth.
The first centerof ossification
for the sternumis presenton the
fifth day with new centersappearingsuccessively
until the ninth day,
when fusionbegins.
Ossificationproceedsrapidly, with articulation and fusion almost
completeby the time the nestlingsare readyto fly.
Departmento[ Biology
WesternReserveUniversity
Cleveland, Ohio
and
EasternStateTeachers'College
Madison, South Dakota