ART. 16 FOSSIL REPTILES FROM MONTANA GILMORE 29 



and shrubbery. Had they not been found in situ, a study of living 

 creatures on the basis of analogy would not have placed them as they 

 are. Reversed in position or at most having the spines directed 

 straight out from the body, would be more in accord with those 

 spined quadrupedal creatures known to-day. Furthermore, the 

 specimen of Scolosaurus in the British Museum has somewhat sim- 

 ilar scutes preserved along the neck in situ, and these are in accord 

 with living lizards. It is not my purpose to question the position of 

 the spines in the Palaeoscincus skeleton but I do seriously doubt 

 that during the life of the animal they occupied their present 

 forwardly directed position. 



Sacral armor. — That Palaeoscincus had a shield-like bony cover- 

 ing over the sacrum as in Nodosaurus seems to be indicated by the 

 presence of a number of large fragmentary plates. These plate 

 pieces are clearly shown to consist of a number of thin, coossified 

 scutes of several sizes and varying shapes, although most of them 

 seem to be suboval in outline. From this fragmentarj'^ evidence it 

 would appear that there may be a row or rows of large scutes sur- 

 rounded by smaller ones. It would seem quite probable that all 

 of these pieces may have been parts of one continuous bony shield. 

 The nodular prominences on these scutes are almost obsolete, except 

 for a slight thickening near the center of the largest. On the dorsal 

 surface shallow depressions follow the course of the sutures, clearly 

 marking out their limits. A few detached scutes of the same nature 

 probably represent elements that pertain to nearby areas. Good 

 examples of these are shown in Plate 7, Figure 1. 



Undetermined scutes. — In addition to the dermal scutes described 

 above and whose position on the animal has been determined with 

 some degree of assurance, there are in the collection no less than 

 twenty other dermal elements whose origin at this time is unknown. 

 These scutes are of various dimensions, strongly keeled, short spined, 

 broadly to narrowly suboval in outline, always excavated below, but 

 usually deepest beneath the highest part of the keel or spine. On 

 either side of the keel the external surface slopes both ways to the 

 edge, either flatly or with a varying amount of concavity, depending 

 largely upon the height of the keel or spine. In none of these 

 smaller scutes does the spine overhang the border. The short 

 spines, if they may be so designated, show a great variety of form; 

 some are obtusely pointed, others compressed and sharp edged, 

 others have the keel running the full length of the scute, while 

 still others have only a nodular projection. 



A great many small rounded granular ossifications were found 

 scattered through the quarry. These filled the interspaces between 

 the larger scutes, and are well shown in specimens of Palaeoscincus 



