Cope.] 1-8 ^Feb. 5, 



grooves cut the margin into deep notches at some points and into shal- 

 lower ones at others. The areas between these sutures are all swollen in 

 the same way as the alternate parts of the costal plates. 



Measurements. 



MM. 



Length of plastron anterior to posterior angle of inter- 

 clavicle 80 



Width of plastron anterior to posterior angle of interclavicle. .112 



Length of interclavicle 40 



Width of interclavicle 58 



Thickness of interclavicle 11 



Length of free lateral margin of giilar plate 29 



Width of base of both gular plates 45 



Length of xiphiplastral bone 32 



Width of xiphiplastral bone on anterior suture 53 



Width of emargination of posterior lobe of plastron 50 



{anteroposterior 20 

 vertical 34 

 transverse below. .. . 25 

 f anteroposterior 29 

 vertical 44 

 transverse below 21 



anteroposterior.. 17 

 rse 30 



Diameters of penultimate vertebral bones ] . .. 



The American tortoise, which has produced gular areas somewhat like 

 those of this species, is the Testudo cultratus Cope of the While River 

 Neocene of Colorado. That species is, however, totally ditferent in the 

 dermal sutures of the usual character, flat marginals, etc., and the gular 

 processes are not conic, but trihedral in form. 



The specimen above described comes from Espuella near Dockum, 

 from the same horizon as that of Crosby county, or the Blanco Canyon 

 bed of Cummins. 



III. On a Mesozoic Pycnodont. 



MiCRODXJS DUMBELII Sp. nOV. 



This species is represented by a splenial bone of the left side, which sup- 

 ports four and a half rows of teeth. The external two rows include small 

 teeth with crowns, which are either round or slightly transversely oval. 

 The teeth of the third row are larger and the crowns are all transversely 

 oval. The teeth of the fourth row are of unequal sizes, commencing 

 anteriorly of about the same size as those of the third low. The third 

 tooth from the front, as preserved, is much larger, but it is exceeded by 

 the fourth ; while the fitih is lialf as large again as the fourth. The sixth 

 and last is a little smaller than the fifth. The teeth of the tilth row are as 



