88 



REVISION OF THE PELYCOSAURIA. 



from the end of the cavity, while in Eryops it is a direct continnation of the radial 

 crest. The shaft is considerably contracted in the middle portion. The anterior face 

 of the distal end is flattened and even concave ; the posterior face has a very deep 

 groove separating the two condyles. The articnlar faces of the condyles look well 

 forward and are connected by a wide area, not separate as in Dimetrodon. The outer 

 condyle is longer than the inner. 



The tibia is slightly curved and has a greatly enlarged proximal end, but the 

 articular face is not so nearly divided into two parts by a depression as in Dimetrodon. 



Fig. 25 a. — Sketch restoration of Theropleura relroversa. About 



Measurements. 



myn. 



Length of maxillary (approximately) 240 



from quadrate to maxillary, estimated 140 



Total length of skull, estimated 380 



Length of premaxillary 56 



Antero-posterior diameter of : 



Large maxillary tooth at base 9-5 



Small maxillary tooth at base 6.5 



Approximate length of column as preserved . 1175 



Length of the nine caudals 255 



Bottom line of axis 3° 



Vertical diameter of axis just posterior to neu- 

 ral arch 32 



Bottom line of ; 



8th, 22 mm.; vertical diameter as in axis . . 30 



30 

 29.5 



29 

 96 



Bottom line of : 

 13th, ig mm.; vertical diameter as in axis. . 

 23d, 20 mm.; vertical diameter as in axis. . 

 29th, 16 mm. ; vertical diameter as in axis. . 

 Height of spine of ; 



Axis above base of centrum 



13th above lower edge of anterior face of 



centrum 105 



Length of nearly complete pelvic symphysis. . 205 



ischium 14° 



across distal end of ilium 91 



Width of acetabulum 85 



Length of femur 188 



tibia 143 



Fig. 26.— Three vertebrae of Theropleura granJis, Nos. 4130-4134 

 Am. Mu9. X /i- a. An anterior cervical, axis or third. /', A 

 mid-dorsal, c, A posterior lumbar. 



Theropleura grandis Case (see p. 28 



and text-fig. 26). 



Characteristic specimens : Nos. 

 4130 and 4134 American Museum. 

 The type, No. 4109 Am. Mus. Nat. 

 Hist., Cope, coll. : A lot of verte- 

 bra, including two presacrals, two 

 sacrals, and five caudals. 



Nos. 4130 and 4134. Three 

 vertebrse are selected as character- 

 istic. The first, fig. 26, a, is either 

 the axis or the third cervical, the 

 centrum is elongate with a low, 



sharp ridge on the median line below. The sides of the centrum are regularly convex 

 and marked by irregular longitudinal lines as in Diopeiis yetroz'ersa. The transverse 

 process rises from high up on the side of the vertebra. The anterior articular face 

 has fairly well-developed centantra and a broad intercentral face below. 



