called “ SteypireySr” by the Icelanders. 329 
If we first examine the atlas, it will appear, from the figure 
given below (fig. 1), that this vertebra presents all the cha- 
racteristics peculiar to it in the Physalus section*, which 
Mr. Flower first pointed out. Thus the rather long trans- 
verst processes evidently enough arise from the upper half 
Bro. de. 
Atlas, seen from behind, one-tenth of the natural size. 
of the sides of the vertebra; they are somewhat compressed 
at their base from before backwards, somewhat tapering to- 
wards the end, and point straight outwards, except near the 
very end, which is bent a little forwards. Further, we find, 
on the posterior surface of the body of the vertebra, not two 
separate, but only one single, horseshoe-shaped articular sur- 
-face for articulation with the axis; and, finally, the vertebra 
wants that median backward-directed triangular process which 
in the Stbbaldius section projects from the under surface of its 
body, and articulates with a special surface on the second ver- 
tebra. ‘The most important dimensions of the vertebra are the 
following :— 
Distance between the extremities of the transverse 
PIOCORSER TN wi wilt iarn lala slag «a OMI AE area aye! Bee 
Greatest height of the vertebra ................ ot LOM 
Heigeivof fhe neuralicanaly 4.08. vad. os wees 3 oe AN 
Greatest width between the outer edges of the arti- 
cular cavities for the occipital condyles ........ ta Gi! 
Greatest diameter of each of these articular cavities 11” 9!” 
Greatest breadth of the horseshoe-shaped articular 
suriace tore amIsie. . Oho ue laced ro sateen oe Prete wenn 
* Or to the genus Physalus, Gray, of 1864, not 1866. 
+ This measurement is not quite accurate, as the ends of both trans- 
verse processes are a little damaged ; but the pieces broken off have pro- 
bably not amounted to more than an inch on either side. 
