scott: ENTELONYCHIA OF THE SANTA CRUZ BEDS. 
249 
difference is sexual rather than specific, for a palate in the La Plata 
Museum, obviously referable to H. cunninghami, has relatively quite 
large and tusk-like upper canines, which are much more prominent than 
in the type ; presumably, therefore, the latter individual was a female. 
The palate in question has been figured by Lydekker (’93, PI. XIX). 
The premolars, which increase gradually in size posteriorly, have a 
decided resemblance in pattern to the molars, yet are easily distinguish- 
able from them and none is altogether molariform. Except in p 1 , in 
which the transverse and antero-posterior diameters are nearly equal, the 
transverse width of the premolar crowns considerably exceeds the antero- 
posterior length. A strong cingulum is developed all around the crown, 
being especially prominent and conspicuous on the internal and external 
sides ; on the latter it is most prominent, rugose and tuberculated. The 
first premolar (p- 1 ) varies considerably in size, both individually and spe- 
cifically, though always the smallest of the series ; it is much smaller in H. 
segovice and relatively quite large in H. cunninghami. In the type of 
the latter species this tooth is somewhat displaced toward the inner side 
and overlapped externally by the canine, but this is no doubt an indi- 
vidual peculiarity, as I have not observed it in any other specimen. The 
crown is supported, according to Flower, by two roots, one internal and 
the other external, and is not very different from that of the canine. It 
is, however, less pointed and conical and lower dorso-ventrally, longer 
antero-posteriorly and broader transversely ; the external face is more 
quadrate and the vertical ridge is displaced to a position which is some- 
what behind the middle. The internal cusp, or deuterocone, is much 
better developed than that of the canine and forms a prominent ridge ; 
the broad valley opens anteriorly and, at least in the moderately worn 
condition, is closed posteriorly by a raised border, which connects the 
internal cusp with the external wall of the crown. From this border a 
large spur projects forward, incompletely dividing the valley into external 
and internal portions, the anterior part of the valley being undivided. 
The remaining premolars (p-, -, A ) have more nearly acquired the molar 
pattern and differ merely in size. Each is implanted by three roots, two 
external and one internal, the latter being very large in p- and A , quite 
slender in p-. I am quite at a loss to understand Ameghino’s statement 
that the upper premolars have “the roots all coalesced into a single one” 
(’98, 172), for I have seen no specimen that would even suggest such a 
