HATCHER: OSTEOLOGY OF HAPLOCANTHOSAURUS 37 
ing of the horizontal branch is of course brought about by the inward curvature of the 
ilium in the region of the acetabulum. 
The fourth parapophysis differs from all the preceding in its widely expanded 
ascending branch which curves very gently backward. The horizontal branch is 
stout and longer than that of the third parapophysis. 
The fifth and last parapophysis differs from all the preceding in the absence of 
any ascending branch. The horizontal branch is greatly expanded vertically, and 
the articular surface for the ilium is elongate so as to give support to the ischiac 
peduncle and posterior blade of the ilium. The principal characters of the para- 
pophyses are well shown in the accompanying figures. 
Only the centra of the fourth and fifth sacrals are preserved. Fortunately these 
are well preserved. ‘The parapophyses of the right side fit very well when adjusted 
to their respective vertebrae. Neither of these vertebree show any marked enlarge- 
ment of the neural canal. They are both constricted medially, and the distal 
extremity of the fifth is considerably expanded for contact with the first caudal. 
The centrum of the fifth sacral is decidedly heavier than that of the fourth. 
The principal measurements of the different sacral elements in the type of the 
present species are as follows : 
Distance along crest of the five codssified sacral spines.. 
wo ay ue ‘¢ four anterior  ‘ He 
‘« from anterior zygapophyses of first sacral to posterior zygapophyses 
Oe 1TH SEYEREA | con oasdosanassncnagondbandadoogoocbGon0onobadeSddoaqadbddesosoboconeaNcEd Ho 575 
Hxpansevondiapophysiscot, thirdisacralernc.s.cmccseesccesesc cee ececeeeeeasteceece 375 
Greatest length of horizontal branch of first parapophysis.....................0+- 213 
He height of ascending  ‘“‘ Hales Uo 8) “Qogacce00d0g00 conendeds 300 
ub length of horizontal ‘‘ UE excaaysle4G7 5 . dbcodqaodsqanacnonosacaa 146 
He height of ascending  ‘“ Bene ee rian, 414) Oe ppanddanadoooduaSDséadoS 300 
oe length of horizontal  ‘ “ third Rb {= ~~ ‘booapasocadoc9a000G0080% 128 
ue height of ascending ‘‘ menage Ue he ~sesgbgeaonoNdodbOBRsHEaS 277 
es length of horizontal ‘‘ PpacolWudehe Wes <1 Nl opadaesscoososaqobnduads 150 
he height of ascending =‘ sea HOS We ie aia nerd aera Meee 250 
“ length of horizontal — ‘‘ “* fifth SO OT iS asee eee cisacereerec cee 225 
Length of fourth sacral centrum’ .... 2.2.2... 50... ..cecceeeesseeesarscarnenseseesecseseieee 132 
Depth ‘' ¢* ee a 
Wal cts Sc “ ori ee M POR Area scaempadencaac cedar oo TannoTenesee 132 
Length ‘ fifth ae SEAS ee Ui sbaddortocadacohocWbensauusdsdbaocese 120 
Depth ‘* “ a eames ee EG a rnaacooracobasqaSnsTesapdoncccnéoon 182 
Viol tcc « Le oe ne Wl Gn jadoabaosoobooanoGoondudcodenoades 181 
