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FOSSIL REPTILIA OF THE 



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 vertebras 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 vertebras 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 with 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 vertebras 

 (Tab. IX, s, s). The remaining vertebras, 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 vertebras, in the present species. 



Perhaps the two vertebras antecedent to the sacral, in which the centrum shows 

 part of the costal surface, might be regarded as lumbar vertebras. 



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, 

 with 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. 



