ERIK A : SON STENSIO 
I 4 
presumably to have been bent in the way described above for several teeth, i. e. so 
that the distal contour of the tooth was convex from one end to another and its basal 
contour was correspondingly concave. The crown is characterized in the first place 
by a very sharp primary longitudinal crista; a secondary longitudinal crista is not 
developed on the part present. Otherwise the sculpture of the crown consists of the 
usual transversal striae. These are strong on the medial side and a number of them 
extend right from the basal margin of the crown to the primary longitudinal crista, 
to which they are attached at almost a right angle. On the lateral side, on the contrary, 
they are finer and only comparatively few reach continuously from the basal margin to 
the primary longitudinal crista. As PI. 2, fig. 10 c shows, the majority are developed 
as a rule only at the basal and distal parts, while the middle part is weak or is 
absent. Both the discontinuous and the continuous ones join the primary longitudinal 
crista at a right angle, as on the medial side. It is also 
noteworthy with regard to the sculpture of the crown that 
a large number of shorter striae, which have nothing corres¬ 
ponding to them -at the basal margin of the crown, are inter¬ 
calated between the distal ends of the striae previously de¬ 
scribed and, like these, are connected with the primary longi¬ 
tudinal crista. The number of striae is in this way consider¬ 
ably larger close to the primary longitudinal crista than at 
the basal margin of the crown. — The appearance of the 
crown and root in section is shown in text fig. 4 C. The basal 
surface of the root is only slightly oblique. 
In the material from Horn Sound I found several fragments 
of teeth which, apart from their small size, seem to differ from 
the tooth P. 98 e only by having almost all the striae, even those on the lateral side, 
extended continuously from the basal margin of the crown to the longitudinal crista. 
The tooth P. 98f (PI. 2, fig. n) also resembles P. 98 e considerably. It has, however, 
a less sharp primary longitudinal crista, a secondary longitudinal crista is present and 
the greater number of the striae, even on the lateral side too, are continuously developed 
and attached to the primary longitudinal crista, or, nearer the preserved end, to the 
secondary one. 
The fragment of tooth P. 98g (PI. 2, fig. 12) agrees in all essentials with P-98f and 
no special description of it is necessary. 
The tooth P. 98 h (PI. 2, fig. 1 3 ) is represented in its present state of preservation 
only by its middle part. It has certainly been somewhat smaller than, for instance, 
P.g8c and P. 98 e. An indication of the principal cone can still be detected and across 
it there is developed a transversal crista which sends out shorter striae to both sides 
and which shows rather strong ramification both at the lateral and the medial end. A 
fairly sharp primary longitudinal crista is present, but there are no signs at all of a 
secondary one, at least on the part of the tooth that is preserved. In other respects 
the sculpture of the crown seems, as far as one can see, to have resembled most 
closely that described on the tooth P. 98 c. ■— A transverse section through this tooth 
is shown in text fig. 4 D. This shows that the crown extended on the medial side 
^ e (} c 0 
Text fig. 4. 
Acrodus spitzbergensis Hulke 
A ll the sections have the medial 
side ,to the right. 
A, section through tooth P. c, 
C, 
All the sections ii 
