MORPHOLOGICAL REVISION OF THE SUBORDER. 



131 



sented iu the figure. A short distance above the base all the spines are marked by a 

 series of short parallel rugose lines, but there is no marked swelling. 



The posterior series of six are posterior dorsals with longer centra and rounded 

 bottom line. The spines have begun to bend backward, approaching the sharp incli- 

 nation of the lumbar spines of other specimens. The fifth of the series has the bottom 

 line sharper, with a ridge divided longitudinally by a shallow median groove, making 

 it appear as a double ridge. 



Measurements. — No. 114 University of Chicago. 



Length of skull from anterior end to posterior 



edge of orbit 225 



Length, bottom line of axis 38 



Height of spine from center of neural canal. . 83 

 Length, bottom line of — 



3d cervical 



4th 



5th. 



6th. 



7th, 



8th. 



gth . 

 loth 

 nth. 

 I2th. 

 13th. 

 14th. 

 15th 

 i6th. 

 17th . 

 i8th. 

 19th 



38 



38 



32 



29 



ist dorsal 29 



25 



27 

 26 



23 

 22 



19 

 16 



13 



27.5 



24.5 



32 



31 



32-5 



34 



35 



36 



37 



33 



30 



Length, bottom line of — 



20th, ist lumbar 28. 



2ISt 



22d 



23d 



24th 



25th 



26th 



27th 



28th, ist sacral 27 



29th 32.5 



30th 30 



31st, ist caudal 20.5 



32d 18 



33d 15 



Length of scapula 33-40 



Width, opposite humeral cotylus 12 



Length of interclavicle 31-32 



humerus igi 



ilium, antero-posteriorly 150 



ischio-pubic symphysis about 276 



No. 4035 American Museum. 



Length, bottom line of axis 34 



Height of spine above neural canal, same .... 76 

 Length, bottom line of — 



3d vertebra 32 



4th vertebra 30 



Height incomplete spine, same 160 



Length, bottom line of 5th vertebra 26 



Height incomplete spine, same 210 



Length, bottom line of 6th vertebra 27 



Height incomplete spine of same 200 



Length, bottom line of 7th vertebra 25 



Height incomplete spine, same 253 



Length, bottom line of 8th vertebra 24 



Height incomplete spine, same 350 



Length, bottom line of 9th vertebra 24 



Height incomplete spine, same 450 



Length, bottom line of ist posterior dorsal. . . 30 



Height incomplete spine of ist posterior dorsal . 825 



Dlmctrodon macrospondylus Cope (p. 52, plates 25 and 26). 



Clepsydrofis macrospondylus. 



Characteristic Specimens : No. 4012 Am. Mus. : The type. No. 1 01 9 University 

 of Chicago : Vertebrte of the posterior dorsal and lumbar region with the intercentrum 

 and spines almost perfectly preserved. Nos. 4054 and 4055 Am. Mus. : Axis and 

 several other vertebrce. 



Nos. 4054 and 4055 Am. Mus.: The axis (figs. 58 and 59) has the usual elongate 

 centrum, with a low, sharp ridge on the bottom line. The anterior face is nearly cir- 

 cular, with a very prominent edge surrounding the notochordal funnel. On the upper 

 edge are relatively large and deep centantra. The posterior face is circular and sur- 

 rounded by a wide, flat border not recurved onto the side of the centrum. The spine 

 is short and relatively stout. The posterior edge is grooved, but not deeply excavated 

 as in Dimetrodon incisiviis. The upper end has an irregular face for ligamentous 

 attachment, and there is a distinct face for the middle of the anterior edge. 



