22 
FOSSIL REPTILIA OF TPIE 
pophyses of the forty-seventh and forty-eighth vertebrae (s, s) which overlie the 
ischium ( 63 ) on the left side of the body. The articular ends of the ischium ( 63 ) and 
of the pubis ( 64 ) are exposed, retaining their connection with the ilium ( 62 ) opposite 
the forty-third to the forty-seventh vertebrae on both sides. The femora ( 65 ) have 
been slightly dislocated forward, and part of the acetabula is thus exposed. 
The bones of the hind fins have preserved their natural relative positions; those 
of the left side, with their part of the pelvic arch, being a little more backward in 
position than those of the right, agreeing, in this respect, with the pectoral limbs, and 
indicating some general movement of the matrix as the cause of such displacement. 
Including the atlas and axis there are twenty-four vertebra3 before that in which 
the pleurapophyses have risen, to articulate wholly with the diapophyses (Tab. XII, d). 
At the forty-fifth vertebra the rib again begins to articulate wdth the centrum ; in the 
forty-sixth the parapophysis forms the lower half of the costal surface ; in the forty- 
seventh it forms a larger proportion, and the whole costal surface is here suddenly 
increased in size, giving attachment to a short, slightly bent pleurapophysis of 
correspondingly and abruptly increased thickness ; that of the forty-eighth vertebra 
is thicker and straighter, and, as the preceding riblet inclines towards its extremity, 
1 conclude that their thick, abrupt, digital ends were ligamentously connected 
with the iliac bone, and that they therefore may be regarded as sacral vertebrae 
(Tab. IX, s, s). The remaining vertebrae, from the forty-ninth to the eighty-fourth, 
will be caudal ; thus there may be reckoned 24 cervical, 24 dorsal, 2 sacral, and 34 
caudal vertebrae, in the present species. 
Perhaps the two vertebrae antecedent to the sacral, in which the centrum shows 
part of the costal surface, might be regarded as lumbar vertebrae. 
The total length of the vertebral column, from the third cervical to the last 
caudal, following its slight undulations, is 9 feet 9 inches. The skull, from the hind 
end of the mandible to the fore end of the symphysis, or snout, is 1 foot 11 inches. 
The first five or six cervicals, from the third, are more or less obscured by pyritic 
matter ; their neural spines show intervals of from three to six lines ; the upper 
margin of the spine rises obliquely from before backward, with the angle rounded off; 
it is thickest at the middle part, where it measures two lines ; that of the fourth 
vertebra has a fore-and-aft diameter of seven lines, the same diameter of the ninth 
is one inch. The pleurapophyses of the tenth vertebra are about an inch in length, 
Vi^ith a subcylindrical body, bent obliquely backward, and slightly tapering to an 
obtuse end. In the eleventh vertebra, the centrum of which is an inch in length, 
about five lines of free surface intervene between the costal and neurapophysial 
articulations. From the pleurapophysis to the summit of the neural spine it measures 
2 inches 5 lines. At the twelfth cervical the pleurapophyses begin to send forward 
the process which marks what may be termed the neck or pedicle of the cervical rib. 
