SYSTEMATIC REVISION 29 



Genus BOLOSAURUS Cope. 

 Bolosaurus Cope, Proc. Am. Phil. Soc, vol. xvn, 1878, pp. 506 and 529. 



Type: An imperfect posterior portion of a skull. No. 4320 Am. Mus. Nat. Hist. 

 Cope Coll. From Texas. 



Original description: "Teeth fixed in shallow alveoli, and with the crowns 

 expanded transversely to the axis of the jaws. The crowns swollen at the base, 

 and with low apex, divided vertically into two equal portions. The posterointernal 

 half in the maxillary series is low and horizontal; the anteroexternal portion forms a 

 low cusp, which has a semicircular section. The teeth of the lower jaw are similar, 

 but the relative positions of the ledge and cusp are reversed. Anterior teeth of 

 superior series composed of external cusp and internal ledge. No enlarged canine 

 or incisor teeth. Bones of face not sculptured." 



Revised description: This is contained in the revised description of the family. 



Bolosaurus striatus Cope. (Plate 7, figs. 4, S, 6.) 

 Bolosaurus striatus Cope, Proc. Am. Phil. Soc., vol. XVII, 1878, p. 506. 

 Bolosaurus striatus Case, Bull. Am. Mus. Nat. Hist., vol. XXIII, 1907, p. 653. 



Type: Same as that of the genus. 



Original description: "Char. Specif. The external surface of the crown is 

 marked to the apex with waved grooves of the enamel. The edge of the elevated 

 cusp, which presents posteriorly in the maxillary teeth, constitutes the abrupt ter- 

 mination of the exterior face, and is serrate by the interference of the sulci. The 

 edge of the basal ledge is slightly serrate. The muzzle is rather elongate, and the 

 sides of the maxillary and dentary bones are plane and smooth. The mandible is 

 rather narrow, and forms a narrow wedge in the profile outline. It rises posteriorly 

 behind the dental line. The teeth are separated by intervals as wide as a tooth. 



"Measurements. 



"Long diameter of orbit No. I 0.0130 



Depth of upper jaw at orbit 0045 



Depth of lower jaw at front of orbit 0050 



Four teeth in 0080 



Elevation of a crown 0025 



Transverse diameter of molar number 2 0025" 



The foregoing description, by Cope, was evidently taken in large part from the 

 type skull, but some portions of the description are evidently taken from a second 

 skull, No. 4321 Am. Mus. Nat. Hist. Cope Coll., and perhaps from other specimens. 



He adds: "A slight modification of the character is found in two imperfect 

 crania. The principal character is to be seen in the teeth. The enamel of the ex- 

 ternal surface of the cusps is not sulcate, but is smooth; and the posterior cutting 

 edge of the cusp is much less distinct. It is, in fact, obtuse and not serrate. The 

 orbit is large, and the front and muzzle are regularly decurved to the premaxillary 

 border. The angle of the mandible is moderately prominent, and is massive and 

 obtusely truncate. The interorbital region is flat in the transverse direction. 



"Measurements. 



"Length of the skull to the mandibular angle 0.050 



Length of the skull to the orbit 015 



Long diameter of the orbit 018 



Width of the interorbital region 009 



Six teeth in 010" 



Revised description: This is contained in the revised description of the family. 



