49 2 Bull eti7i American Museum of Natural History. [Vol. XIX, 



the latter regularly hexagonal, and they are separated by well- 

 defined grooves." Cope's type specimen is not available for 

 comparison; it may prove that Cope's description and Leidy's 

 reference are both misleading. 



Glyptotherium texanum, gen. et sp. nov. 



The carapace measures 1450 mm. (4 ft. 9 in.) along the 

 dorsal curvature anteroposteriorly, and 1920 mm. (6 ft. 4 in.) 

 from side to side; the tail armature is 620 mm. (about 2 ft. 

 I in.) long, having a circumference proximally of 705 mm. 

 The larger plates in the dorsal region measure 60 mm. in the 

 longest diameter, which is oblique to the axial line of the 

 carapace. The marginal plates may be estimated at 84, or 

 42 as counted on the more perfectly preserved left side. 

 Eight of the posterolateral marginal plates are pointed or pro- 

 jecting; all the others have an even, gently convex, border. 

 The central plates are quadrate in the lower portion of the 

 shield, irregularly pentagonal and hexagonal in the upper, 

 all being characterized by a large central circular area sur- 

 rounded by from 7 to 12 smaller peripheral areas, all sepa- 

 rated by grooves. From 35 to 36 transverse rows of these 

 plates may be counted along the top of the carapace, and 34 

 at the side, practically the same number as in Glyptodon clavipes 

 Owen.^ The six anterolateral rows are firmly united, but the 

 seventh to fifteenth are separated by deep grooves and ad- 

 mitted of some freedom of motion; these plates overlapped, 

 the borders being bevelled. A similar freedom is observed in 

 Panocthus. 



The tail armature is composed of eighteen circles of plates, 

 of which the anterior fifteen are arranged in paired rings and 

 the posterior three are coalesced into a single triple piece or 

 terminal cone. There are thus eight of the movable rings, of 

 which the seven anterior are composed of two rows of simple 

 flattened plates, and the eighth of a single row of elongate 



' Cf- Lydekker, R., Contributions to a Knowledge of the Fossil Vertebrata of Argen- 

 tina, Pt. II., pll. i-v. Paleontologia Argentina, III. La Plata, 1894. 



