36 
ERIK A : SON STENSIO 
The sculpture of the crown is incompletely preserved. It is evident, however, 
that a longitudinal crista has been present and that this crista was situated somewhat 
on the lateral side of the median line of length. One can also see that dense trans¬ 
versal striae have issued, at least anteriorly, from the longitudinal crista to both sides. 
The root, though preserved on a number of teeth ' in the row in question, is not 
accessible for any detailed investigation. 
Row b (text fig. 14, PI. 3 , figs. i 3 , 16 a, b) consists of seven teeth, which are consider¬ 
ably larger than those in row a. Their length is about 14—15 mm, the maximum 
breadth 3 — 3 ’5 mm and the greatest height about 5 mm. 
Their arrangement is such that the axis of length through each of them is fairly 
parallel with the labial margin of the mandibula. Their relative positions are the same 
as in the teeth in the row in front. 
Seen from the lateral or the medial side they are bent in the usual way so that 
the masticatory surface is convex from one end to the other and the basal surface of 
the root is concave in the same direction. The curvature is strongest, however, somewhat 
caudally of the middle and the highest part of the crown is also 
situated at this place, as shown in text fig. 14. 
The caudal end of the crown is truncated. From it to the 
highest part the crown is of uniform width (PL 3 , fig. 1 3 ); in front 
of the highest part it grows gradually narrower and the anterior 
end thus gets rather pointed. The crown and the root are both 
of about the same height. With regard to width, however, the root 
is far exceeded by the crown and in connection with it a very 
prominent notch is developed on the medial side (text fig. 15 A). 
The part of the surface of the crown that forms this notch faces medially and at the 
same time basally and is separated by a sharp angular longitudinal edge from the 
real masticatory surface (PI. 3 , fig. 15). When I speak of this below I shall call it the 
baso-medial surface of the crown. The real masticatory surface is only weakly arched 
from side to side. It passes in a well rounded edge into a lateral surface (PL 3 , fig. 14) 
that is fairly vertical and that I shall call in the subsequent description, the lateral 
surface of the crown. 
On the real masticatory surface we find fairly close to the edge between it and 
the lateral surface a fine longitudinal stria or, if one likes to call it so, a longitudinal 
crista. From this there issue to both sides dense fine striae with abundant ramifications. 
Laterally of the longitudinal crista all the striae pass off quite transversally and continue 
on the lateral surface of the crown right to the basal margin. Medially of the same 
crista, on the other hand, they only reach the angular edge between the masticatory surface 
itself and the medial surface of the crown. Their course is such that their part situated 
nearest to the longitudinal crista bends round towards the highest part of the crown and 
in this way meets the longitudinal crista at an acute angle. Those situated in front of 
the highest part, on the other hand, are bent forwards. All the striae, both medially and 
laterally of the longitudinal crista, form only a few anastomoses (Pl. 3 , figs. i 3 , 14, 15). 
The root (text fig. 15 A, Pl. 3 , fig. 15) has a plane, well developed basal surface, 
which is so situated that the axis of height of the crown meets it at right angles. 
Text fig. 15. 
Palaeobatespolaris n. sp. 
A. Cross section through 
tooth belonging to the trans¬ 
versal row b. Medial side to 
the left. 1/1. B. and C. Two 
teeth belonging either to one 
of the most anterior rows 
or more probably to an un¬ 
paired symphyseal row. 
