MOODIE: ARMORED CRETACEOUS DINOSAUR. 263 



tion cannot be entirely attributed to the age of the individual 

 but is expressive rather of the higher specialization of the pres- 

 ent form. 



Attached to the neural spines of the sacral elements was a 

 long, narrow dermal plate (plate LVI, fig. 3), evidently in firm 

 union with them. This plate occupied the mid-dorsal line of 

 the great pelvic shield and lay between the iliac armor of the 

 two sides. The plate, like all the rest of the dermal skeleton, is 

 scrobiculate and somewhat of the texture of woven cloth, as 

 Marsh has described in Nodosaurus textilis (11). It becomes 

 slightly expanded posteriorly, where it measures 30 mm. in 

 width. 



The caudal vertehrse (plate LIX, fig. 1, and plate LVIII, 

 fig. 3) vary to a remarkable degree from those of the dorsal 

 series. They are greatly compressed dorso-ventrally ; are very 

 short, with the sides much rounded and the centra plano-con- 

 vex. The vertebrae have strong transverse processes. In 

 neither specimen is the neural spine preserved, so it is im- 

 possible to say as to its extent. This, however, may be inferred 

 to have been low and stout, if one may judge from its broken 

 bases. The neural canal is not large, measuring only 14 mm. in 

 diameter. The centra measure 82 mm. in width by 38 mm. in 

 length by 41 mm. in height. It is thus seen that the caudal 

 vertebrae are more than twice as wide as long. This condition 

 is not a unique one, since Hulke {12) has described the same 

 condition in Polacanthus. 



The 7-ibs are all so fragmentary that no discussion of them 

 can be given. Many of the fragments are triangular in cross 

 section, agreeing in this respect with other armored dinosaurs. 

 Attached to some of the rib fragments are found small bony 

 scutes. The fact is of service in determining the position of 

 these dermal scutes on the body of the animal. 



The ulna (plate LIX, figs. 8 and 9) of the left side is pre- 

 served complete. It shows considerable variation from any- 

 thing hitherto described for any other armored dinosaur. The 

 shaft of the bone is flattened from side to side and is twisted 

 from right to left. It ends in a rather pronounced expansion 

 distally. The coronoid process is quite prominent and is ex- 

 cavated to form a large sigmoid cavity. The olecranon is long, 

 measuring 70 mm. in length from the base of the coronoid 

 process to the proximal end of the bone, It is flattened from 



