SYSTEMATIC REVISION OF THE SUBORDER. 53 



"The edges of the centra are not undulate or laterally flared. The centra are 

 strongly compressed, and in the anterior part of the column have an obtuse hypapo- 

 physial keel. The intercentra display equal width of the inferior surface; and are 

 abruptly rounded at the extremities. The last one preserved is between the second 

 and third caudal centra. It is shorter and wider than the others, and does not display 

 any trace of a chevron bone. The diapophyses are opposite the neural canal on the 

 thirteen anterior verteljrce preserved. Each one sends a horizontal rib forwards to 

 the prezygapophysis, and another obliquely forwards and downwards which stops 

 short of the edge of the centrum. These ribs enclose a fossa in front of the diapo- 

 physis. Posteriorly the antero-inferior rib grows more robust, and evidently supports 

 part of the tuberculum of the rib. There is no facet for the capitulum till the ante- 

 penultimate vertebra of the anterior series is reached. Here on the penultimate the 

 anterior border is flattened into a facet, and on the last of the series, the facet marks 

 the summit of a distinct tuberosity, which is produced by the cutting away of the 

 border below it, to accommodate the intercentrum. 



"The three lumbar vertebrae preserved are different from the dorsals in their 

 greater abbreviation. This character is not unknown in other species of Pelycosauria. 

 The centrum is contracted, but not compressed, at the middle. The diapophysis is 

 altogether on the centrum, and supports no rib-facet. Its antero-inferior buttress is 

 well developed, extending to the margin of the centrum, which is cut out below it for 

 the intercentrum. The sacnim is rather robust. Its two vertebrae are not coossified, 

 and support well-de\'eloped neural spines, and a large free diapophysis for the ilium. 

 The centra of the caudals, and their diapophyses and neural spines are well developed. 

 There is a fossa at the base of the spine on each side, in line with the zygapophysial 

 surfaces, equidistant between them. 



"The fragment of the ilium is of appropriate size, and is quite robust. It displays 

 the fossa for the sacral diapophysis, and the acetabulum. The latter is remarkable for 

 the prominence of the tuberosity on the superior border, which exceeds that of any spe- 

 cies of Pelycosauria known to me. The section of the ilium through it is triangular. 



" The dentary bone is accompanied by the splenial to the middle of the symphj'sis. 

 The latter is not ver}' long. Its dentary portion turns upward. The ramus is quite 

 robust, differing from that of C. leptocephalus. It is broken off a little anterior to the 

 tooth line, but the latter probably did not contain more than twenty-two teeth. 

 These have anterior and posterior cutting edges and are denticulate. The external 

 face of the dentary is excavated by shallow, undulating, branching grooves." 



Measureineyits, 



m. m. 



Total length of vertebrae preserved 0.640 Diameters of a lumbar centrum, cont'd: 



Diameters, centrum of a dorsal vertebra; Transverse at end 0.026 



Antero-posterior 031 middle 023 



Vertical behind diapophysis 019 Vertical behind arch 022 



Transverse at end 021 at end 029 



middle 0115 Length of sacrum 055 



Diameters neural arch of same vertebra: Diameters of third caudal vertebra: 



Length with zygapophyses 041 Antero-posterior 024 



Width at prezygapophyses 022 Vertical at end 023 



Diameters neural spine of the same vertebra: Transverse at end 022 



Antero-posterior 0145 Antero-posterior diameter of acetabulum 0325 



Transverse behind 007 Transverse diameter of ilium at tuberosity .0265 



Diameters of intercentrum of do.: Length of dentary bone supporting twenty 



Antero-posterior .0032 teeth 044 



Transverse 023 Thickness at twentieth tooth 0175 



Diameters of a lumbar centrum: Depth ramus at second tooth 035 



Antero-posterior 024 fifteenth tooth 039 



