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perforated vertically on one or both sides by epineural canals (fig. 7, en, en) in the 

 third to the seventh vertebra;; each neurapophysis is also perforated lengthwise near 

 the inner surface by " entoneural canals " (fig. 8, in), the orifices being within the neural 

 arch ; they are largest in the sixtli and seventh cervicals, but coexist here with the ver- 

 tebro-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, c), 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 (PI. LXVII. fig. 9, D i,ns). 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 are 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 epineural 

 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 depressed. After the third 

 dorsal the neural spines gradually become shorter and gain in fore-and-aft breadth to 

 the eleventh dorsal (fig. 10, D 11, ns). In this vertebra a short broad metapophysis (m) 

 rises above the base of the prsezygapophysis, and clasps the end of the postzygapophysis 

 of the tenth dorsal. The neural spine (ns) becomes vertical in the eleventh dorsal, 

 indicating the centre of motion of this part of the vertebral column. In the twelfth 

 dorsal (ib. D 12), the metapophysis (m) suddenly gains in size ; it is compressed, truncate, 

 and exceeds the diapophysis (d) in length. The prsezygapophyses are represented by 

 nearly vertical articular surfaces on the inner and fore part of the base of the metapo- 

 physis. An anapophysial ridge (a) is developed from the upper and back part of the 

 diapophysis (d). In the thirteenth dorsal the anapophysis (ib. fig. 10, d 13, a) projects 

 backwards from the hind part of the neurapophysis as a distinct process, five lines in 

 length ; it clamps externally the base of the metapophysis of the first lumbar. The 

 convexity of the fore part and concavity of the hind part of the centrum is retained 



