HATCHER: OSTEOLOGY OF HAPLOCANTHOSAURUS 31 
closely resembles the vertebra just described. The pleurocentral cavities however 
are more completely divided into anterior and posterior moieties by the presence of 
more pronounced oblique laminze. There is a single large infracentral cavity and 
the cup is broader than deep. ‘The anterior zygapophyses are supported inferiorly 
by short and rather slender inferior branches of the prezygapophysial laminze while 
inferior branches of the diapophysial Jaminze give support to the broad diapophyses 
which bear at their extremities the tubercular rib facets. The position of this ver- 
tebra in the quarry is shown at 3 in the diagram. 
The Ninth Cervical (Plate II., Fig. 9, Series 4).— This vertebra found at 4 in the 
diagram of the quarry was not far removed from the preceding. It consists of the 
centrum with the posterior and anterior zygapophyses still in position. It is much 
crushed and distorted but in so far as it is possible to determine, it agrees fairly 
well with what we should expect to find in the ninth cervical. It has been errone- 
ously drawn as complete in Plate IT., Fig. 9. 
The Tenth, Eleventh, Twelfth and Thirteenth Cervicals (Plate IL., Figs. 10, 11, 12, 13, 
Series 3). — These four vertebrie are in each instance well-nigh perfect and they dis- 
play such a gradation of progressive characters that there can be no doubt as to 
their constituting a continuous series. 
The neural spines and posterior zygapophyses become successively more elevated 
as we proceed backward in the series. ‘The spines however show no tendency to 
divide, there being scarcely an emargination at the summit even in the last of the 
four. ‘The posterior zygapophyses become successively more expanded and the supra- 
postzygapophysial cavities become deeper and broader. The position of these 
vertebree in the quarry was as follows: The tenth was found at 5, the neural arch 
and spine of the eleventh was found at 6, and the centrum at 6’, the twelfth is 
shown at 7 and the thirteenth at 8. 
The Fourteenth Cervical (Plate I1., Fig. 14, Series 3). — Only the centrum of this 
vertebra was recovered; it was found at 9 on the diagram. It is considerably 
crushed, especially anteriorly but there is no doubt that it was a cervical and that 
its position was posterior to the thirteenth. Its size, length and general characters 
indicate that it belonged immediately behind the thirteenth I have, therefore, re- 
garded it as the fourteenth. 
The Fifteenth Cervical (Plate I1., Fig. 15, Series 3). — This is represented by a well- 
preserved neural arch and spine without centrum found at 10 as shown on the dia- 
gram. ‘he difference between this spine and that of the thirteenth is such as to 
preclude the possibility of its pertaining to the fourteenth or immediately succeed- 
ing cervical. I have, therefore, assigned it to the fifteenth or last cervical, with 
