EDENTATA OF THE SANTA CRUZ BEDS. 151 



This species is very distinct from the preceding one, from which it 

 differs notably in the conformation of the cephalic shield and in the 

 pattern of the teeth. The shield (Plate XXI, fig. 3) is somewhat smaller 

 than in E. petestatus and it is of quite a different form, the lateral borders 

 being more constricted, or notched, at the junction of the first and second 

 rows of plates. The first pair of plates are smaller, as is also the median 

 unpaired plate of the entire structure, the middle scute of the second row; 

 on the other hand, the two posterior pairs of median plates are relatively 

 larger. The sutural borders are raised into very prominent and jagged 

 ridges, which are much more conspicuous than in either of the other 

 species, and each of the plates has a central pit, which is especially strik- 

 ing in the median pair of the third row ; here the pit has an irregularly 

 circular shape, with raised margin and very rough sides, and at the 

 bottom a small cone, the whole resembling a minute model of a volcanic 

 crater-ring enclosing a cone of eruption. 



The teeth (Plate XXIV, Fig. 9) resemble those of Propalczohoplophorus 

 rather than those of E. petestatus, especially in the anterior region. In 

 the upper jaw - is rather large with elliptical grinding surface and is set 

 obliquely to the line of the other teeth so as to approach its fellow of the 

 opposite side ; - is larger, less oblique and made obscurely trilobate by 

 two vertical grooves on the inner face and a somewhat less distinct 

 groove on the outer; - is still larger and more distinctly trilobate on the 

 inner side. The remaining teeth do not differ in any important way 

 from those of E. petestatus, but have a rather more slender and delicate 

 appearance. 



It is not yet practicable to make a comparison of the skull (Plate 

 XXIX, figs. 1-5) with that of the preceding species, but one difference 

 is sufficiently obvious, namely, that in E. complicatiis the rostrum is 

 relatively less elongate and much broader at the base. On each side of 

 the hard palate, opposite the hinder end of A , is a large foramen, from 

 which a groove runs forward nearly to the premaxillary border ; in addi- 

 tion, the palate is perforated by the usual number of vascular foramina. 

 The posterior narial canal has a large dorso-ventral diameter. 



The following measurements are from the type specimen (A. M. N. H., 

 No. 9248), which was collected by Mr. Brown. 



