PROFESSOR OWEN ON MACROPUS. 427 
The transverse processes of the other five cervical vertebre are perforated. The 
spine of the third is compressed, laminate, truncate, coextensive with the neural arch; 
in the fourth (ib. fig. 7, ms) it contracts antero-posteriorly, loses height, but gains in 
breadth at its summit; this character of the spine increases in the fifth; the spine 
lengthens and becomes obtusely pointed in the sixth, is still longer and more merits 
the name of spine in the seventh cervical (ib. fig. 9, c, ns). 
The parapophysis projects as an angular plate in the fourth (ib. fig. 7, y) and fifth, 
and more so with increased thickening in the sixth (ib. fig. 8, p); it is reduced toa 
mere tubercle in the seventh cervical, in which the pleurapophysis is longest and 
strongest. 
The neural arch is perforated vertically on one or both sides by epineural canals 
(fig. 7, en, en) between the fore (z) and the hind (z') zygapophyses in the third to the 
seventh vertebree; each neurapophysis is also perforated lengthwise near the inner 
surface by “ entoneural canals” (fig. 8, a), the orifices being within the neural arch; 
they are largest in the sixth and seventh cervicals, but coexist here with the vertebro- 
arterial canals (ib. figs. 8 & 9 c, v) in their usual position external to the arch. The 
anterior surface of the centrum is transversely concave (figs. 7, 8, ¢), the posterior one 
convex in all the cervicals following the axis. 
The entoneural canals are repeated in the first dorsal, which shows a sudden increase 
in the length of the neural spine (Pl. LXXV. fig. 9,p 1, ”s). The transverse concavity 
of the fore part of the centrum, as in the cervicals, is retained in the first dorsal ver- 
tebra. ‘There is one large cup for the head of the first thoracic rib on each side of the 
anterior half of the centrum and contiguous part of the neurapophysis. This element 
(ib. n) articulates and has coalesced with the corresponding part of the centrum, leaving 
the hinder half free. The half-cup for the second rib impresses the angle between the 
hinder concave articular surface and the free lateral surface of the centrum. 
The strong diapophysis is impressed below its outer end by the large and deep cup 
(ib. d) for the tubercle of the first rib, The right side of the neural arch has an epineural 
canal. 
The second dorsal (ib. fig. 9, D 2) has a longer and more slender spine (ns). The 
neural arch shows the vertical perforation on the left side. The intraneural canals aré 
reduced to two minute posterior perforations. The anterior articular surface of the 
centrum is convex. In the third dorsal (ib. fig. 9, D 3) the centrum lengthens and the 
sides are defined by an angle from the under surface. There are neither ento- nor epi- 
neural foramina. 
The anterior costal pit in this and succeeding dorsals seems to be a mere folding-back 
of the outer ends (fig. 9, D 3) of the anterior convex articular surface of the centrum. 
In like manner the half-surface for the head of the next rib seems to form the outer end 
of the posterior transverse surface of the centrum. 
The diapophyses (ib. d) increase in antero-posterior extent and become more de- 
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