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G. J. DE FEJ Éli VA 11 Y 
ding to the proc. spinosus is much damaged; as‘in V. griseus it is here 
also hut slightly elevated and forms the ridge of the tectiform median 
portion in the front part of the upper arch. There is a large fractured 
surface on the median line of the posterior section (fragment of the 
upper arch), forming the base of the bony crest of proc. spinosus, which 
must have been strongly projecting in that region of the vertebral co¬ 
lumn ; this bony crest is unfortunately no more to be seen, the last ves¬ 
tige of it being a very slight elevation on the right side of the fractured 
surface. The median part of the arcus vertebrae is somewhat arched, 
whilst the posterior part on both sides of proc. spin, extends obli¬ 
quely downwards ; only the two hollows mentioned are seen on both sides 
of the front median tectiformf region of the upper arch ; the latter one, 
when viewed from above, presents the outline of an æquilateral tri¬ 
angle : the two hollows afterwards disappear in the lateral elevation 
extending gradually along the sides of the upper arch. A close examination 
of the surface reveals the delicate concave arch-like structure-lines traceable 
between the periphery and proc. spinosus. 1 In their basal type the proc. 
obi. post, bear a certain resemblance to the cervical vertebra, although 
decidedly wider and less curved downwards, again very slightly rising in 
the direction of their lateral periphery. The lateral (rather lower) surface 
(=«urface of attachement) is leaf-shaped, much broader however than on 
the cervical vertebra, and sharply detached on its periphery. The arcus 
vertebrae is low and stout; on the hind edge of its proc. obi. posteriores 
two tolerably parallel-sided surfaces (uppe r part of facies rhomboi¬ 
dales mihi) of approximately 3*5 mm in breadth extend obliquely to¬ 
wards the proc. spinosus; the inferior border of these (beginning somewhat 
before the extremity of the lower edge of the lateral (lower) surface of 
proc. obi. post.) forms a very obtuse angle (of about 150°), after which, 
on each side, the lower parts of the rhomboidal surfaces may be 
Seen, these being about as wide or rather wider than the upper ones ; 
in the median line (at the junction of the two rhomboids) a slight bony 
elevation (linea medialis mihi) stretches down to the point where 
the dorsal part of the spinal canal wedge-like projects forward between the 
two rhomboidal surfaces, whose lower borders form the lateral edges 
of the wedge. (See PI. II, Fig. 10.) I have not observed this différenciation in 
surface in V. griseus ; with this latter the region in question is merely 
represented by a single acute angled surface directed towards the spinal 
canal (forming a part of the lower surface of proc. obi. post.). The spinal 
1 Tiie course of these also proves to the fact of the two fragments belonging to 
the same vertebra. 
