32 PROCEEDINGS OF THE NATIONAL MUSEUM vol.77 



pally of the posterior part of the axillary skeleton. Of the head 

 only fragmentary skull parts and a few teeth remain. 



In the 1928 collection from the Upper Cretaceous of Montana was 

 a somewhat imperfect skull with four teeth which is identified as 

 DyoflosauTus acutosquameus Parks. The identification rests very 

 largely upon similarities found in the teeth. If correct in this as- 

 signment, the specimen is of great interest in giving the first ade- 

 quate knowledge of the skull structure of the genus. This specimen, 

 No. 11892, U.S.N.M., was collected by George F. Sternberg, May 26, 

 1928, from the Two Medicine formation, Upper Cretaceous, from the 

 south side of Milk River, NW. lA sec. 27, T. 37, N., R. 8 W., on the 

 Blackfeet Indian Reservation, Glacier County, Mont. 



The skull has its closest resemblances in Euoplocephalus tutus 

 Lambe from the Belly River formation, Canada, of which two 

 nearly perfect skulls ^^ are now known in addition to the poorly 

 preserved type. 



The skull before me has the superior surfaces much checked as 

 shown in Plate 9. It lacks the beak in front of the nares, and the 

 palate is so badly crushed and broken that little can be determined 

 of the mouth structure. 



Viewed from above the skull is subtrianguiar in outline, longer 

 than broad, and doubtless having a broadly rounded nose as in 

 Euoplocephalus. The anterior half is strongly arched both antero- 

 posteriorly and transversely. Between and behind the line of the 

 orbits the top is depressed, especially on either side of the median 

 line. This surface terminates posteriorly as a short overhanging 

 crest, that is, slightly concave transversely. 



Coossified dermal plates cover the surface at the top and side of 

 the skull, thus completely obscuring all of the underlying cranial 

 elements. The median posterior border is ornamented by a row of 

 four small quadrangular scutes, the same number as found in the 

 fragmentary skull of the type of Byoplosaums acutosquameus. 

 Ankylosaurus also has a similar number, but in Euoplocephalus 

 there are only two with a plain interspace between. The superior 

 surface is so badly checked that the form of the scutes can be made 

 out with great difficulty. They seem to resemble those of Euoplo- 

 cephalus except for the lack of a large element on the nose. The 

 surface of these scutes is undulatory, roughly rugose and covered 

 with vascular pits and grooves. Their edges are usually angular 

 but none has the depressed central areas found in Euoplocephalus. 

 Deep circumscribing grooves set off the scutes from one another. 



=»Gilmore, C. W., The Canadian Field Naturalist, vol. 37, No. 3, 1923, p. 47; Nopcsa. 

 P. B., Geologia Hungarica Paleontological Series, vol. 1, 1928, pp. 51-54, pi. 5. 



