54 PEOFESSOE OWEN ON THE 



The hypapophysis of the first of the three expands at its termination (PI. XVI. fig. 1, 

 hj), with the hinder angle bent back to coalesce with the front one of the next hypapo- 

 physis, which is somewhat longer, and bent forward with a similar terminal expansion : 

 a full elliptical space is intercepted by this tenninal confluence of these hypapophyses 

 (PI. XVII. figs. 1 & 5, hy). Each vertebra shows an elliptical articular cavity (ib. figs. 

 1 & b, J), 2^ ■') foi" ^^^ ^ead of the rib, near to the anterior articular surface ; the long 

 axis of this costal surface is directed from above obliquely downward and forward. The 

 surface of the rib's tubercle cuts obliquely the lower part of the free end of the dia- 

 pophysis (PI. XVI. fig. 1, d). 



The neural arch circumscribes a canal the anterior outlet of which (ib. fig. 1, n) is 

 o^al with the small end downward, 5 lines in vertical, and 3 j in transverse diameter : 

 the sides of the neural canal shghtly project inwai'd above the lower third : the posterior 

 outlet (PI. XVII. fig. 4, n) is more regularly elliptical in form, and rather narrower in 

 proportion to its vertical diameter. The neurapophysis sends off from the outer and 

 fore part of its base a stout process, which expands and divides into zygapophyses (PI. 

 XVI. fig. 1, z) and diapophyses (ib. d) ; the articular surface of the former is of a 

 full oval shape, flat, looking obliquely upward and inward; the diapophyses extend 

 outward and a little backward : the articular surface for the tubercle of the rib is 

 transversely elliptical and nearly flat. The hinder part of the neurapophysis expands 

 into the postzygapophyses : these have coalesced with the prsezygapophyses in the suc- 

 ceeding vertebra (PI. XVII. fig. 2, z), as has happened also between this and the thu-d 

 vertebra. In the last of the three vertebrae the postzygapophyses are entire (ib. z s), 

 and show very slightly concave, oval articular surfaces, looking obliquely downward and 

 outward (ib. fig. 4, z). The conjugational foramina, continuously surrounded by bone, 

 are a fuU ellipse, and large, the anterior one (ib. figs. 1 & 5,_/') being 5^ lines in vertical 

 diameter; the second (ib.y) is somewhat less: these foramina are also rather larger in 

 one of the specimens than in the other. The length of the three coalesced dorsals is the 

 same in both, ^'iz. 2 inches 3 lines. The neural spines have run together into a con- 

 tinuous ridge in fig. 1, ms ; in fig. 5 the summit is broken ofi" in both, lea%'ing only the 

 anterior angle of the foremost entire ; in both this inclines forward ; the hinder border 

 of the third vertebra (fig. 1, ns) has the same vertical parallel as the back part of the 

 centrum. The anteiior margin of the base of the spine shows a rough surface for the 

 attachment of ligament (PI. XVI. fig. 1, ns). A small foramen behind the base of each 

 of the coalesced zygapophyses (PI. XVII. fig. 2, z z) leads to a canal descending to 

 the neural one, and indicates superiorly the limits of the otherwise continuously ossified 

 neural arches. 



In the series of detached vertebrae, one (PI. XVII. fig. 6 & 7) indicates by its neural 

 spine and hypapophysis a position at the base of the neck. The centrum is barely an 

 inch in length ; its anterior surface (ib. fig. 7, c) is naiTOW vertically, broad transversely ; 

 both fore and hind surfaces indicate freedom and extent of flexure. The hypapophysis 



