4 
In the twelfth cervical the hypapophysis is reduced to a short triangular process, and 
the neural spine forms a low thick knob; the pleurapophyses are still anchylosed as 
mere processes, 
In the thirteenth cervical they elongate, but are fixed; the hypapophysis is a mere 
tidge ; the parapophyses reappear as ridges; the diapophysis is widely cleft, and the 
hinder and lower portions afterwards alone represent this process; the neural spine is 
a higher tubercle than in the twelfth vertebra. 
The fourteenth vertebra, retaining its pleurapophyses as free elements, may be 
reckoned as the first dorsal (Pl. I. fig. 1, p); its centrum is broader than it is long, 
with a medial and two marginal ridges below: the first ridge is hypapophysial ; the 
latter are parapophysial, and are most produced, each bounding a concavity on the 
under surface of the vertebra. The pleurapophysis (ib. p/) is a simple, straight style, 
6 lines in length, articulated to the under part of the base of the diapophysis, which is 
now a broad, triangular, depressed plate. The neural spine is a strong, compressed, 
quadrate plate in this and the succeeding dorsals. 
In the second dorsal the parapophysial or lateral hypapophysial ridges are more pro- 
duced, especially at the hinder angle. The pleurapophysis is a long, nearly straight 
style of about 3 inches in length, and supports at the beginning of its lower or distal 
third an epipleural plate curving upward. The head of the rib is expanded and articu- 
lates to much of the under part of the diapophysis. The quadrate neural spine gains in 
fore-and-aft extent. 
In the third dorsal the lateral hypapophysial plates are longer and narrower, and 
begin to be supported as processes from the descending inferior part of the centrum. 
The pleurapophysis, 3 inches 7 lines in length, articulates above by a head and tubercle 
with the centrum and under part of the diapophysis, and below with a straight hemapo- 
physis, 1 inch 5 lines in length, and expanding at its sternal end to articulate with an 
oblong cavity, transverse to the broad costal margin of that bone. The epipleural is a 
plate 1 inch in length, and from 1 to 2 lines broad. 
In the fourth dorsal (Pl. LU. tig. 7), the parapophyses are converted into a hy papo- 
physis in the form of a broad bifurcate process, the prongs diverging at a wide angle as 
they descend from the common produced base (hy). The pleurapophysis, with the 
head more distinct from the tubercle, and supported on a longer neck, is 4 inches in 
length, and articulates with a hemapophysis 1 inch 10 lines in length. The diapo- 
physes (ib. d) are long and broad; the zygapophyses (ib, s, 2’) small and short. The 
neural spine (ib, ns) increases in antero-posterior but not in vertical diameter, and 
preserves the quadrate form. 
In the filth dorsal, the stem of the bifurcate hypapophysis lengthens. The pleurapo- 
physis, 4 inches 10 lines in length, continues as slender as the precediug, and articu- 
lates with a heemapophysis 3 inches 2 lines in length, and slightly bent. 
The sixth dorsal has a longer and narrower stem of its bifurcate hypapophysis ; but 
