86 
ERIK A : SON STENSIO 
The membrane bones of the cheek. 
Of the cheek-plates the following are present in a more or less fragmentary con¬ 
dition: the lacrymo-jugal (text fig. 38 x^; La. ju, PI. io, fig. 3 ), postorbital (. Po , text 
%• 35 ; PI. 10, figs. 1, 3 ) squamoso-preopercular (Sq. pop, text fig. 35; PI. 10, figs. 1, 3), 
a smaller plate {a, text fig. 35; PI. 10, fig. 1) situated behind the postorbital, and probably 
also the preoperculo-quadratojugal Pop. quj?, text fig. 35; PI. 10, figs. 1, 3 ). Their mutual 
relationship with regard to position and size seems to be essentially the same as in 
W. sinuosa, and this seems broadly to be true of their shape as well. It is also evident 
that they have been situated fairly loosely in relation to each other, but whether to the 
same extent as in W. sinuosa, is, however, uncertain. With regard to the plate a situated 
behind the postorbital I have already shown above (cf. Wimania sinuosa p. 77) that it 
seems to correspond to a dorsal part of the squamoso- 
preopercular. It is triangular in shape. — All the cheek- 
plates have a characteristic sculpture of flat, rounded tubercles 
situated exceedingly close together and sometimes arranged 
concentrically (PI. 10, figs. 1, 3 , 6). 
Visceral skeleton. 
Of the metapterygoid ( Mptg, text fig. 35; PI. 10, fig. 1) 
only a posterior part is preserved. The shape is accordingly 
rather uncertain, on the whole, nor can its position relative 
to the pterygoid be decided' exactly, whether it extended 
posteriorly in a caudal direction a little behind that bone 
in the way seen in the type specimen of text fig. 35, and 
PI. 10, fig. 1 or whether the conditions were the same as 
in W. sinuosa. 
The pterygoid (Pt. text figs. 35, 36 ; PI. 10, figs. 1, 4) 
is so preserved that a part of its posterior limb is present 
in thespecimen P.225, and practically the whole of the anterior 
limb in the one P. 226. In text fig. 36 I have tried to recon¬ 
struct the appearance of the bone as a whole with the help 
of the remains mentioned, but it must be pointed out that the 
width of the posterior limb, like its height too, is rather uncertain in relation to that of 
the anterior one. The posterior margin of the posterior limb is slightly convex. The dorsal 
margin is on the contrary slightly concave and slopes rather rapidly backwards, i. e. it 
faces dorso-caudally. The postero-dorsal corner is obtuse-angled; the ventral corner is prob¬ 
ably well rounded off. The posterior part of the anterior limb is very high, and this high part 
is also strikingly broad. The upper margin of this limb has a very characteristic course. Farthest 
posteriorly it is fairly horizontal for a short distance, then it bends round downwards and for¬ 
wards, continuing in this direction for a considerable distance, then rather suddenly taking 
a direction almost straight forward and, with this direction, then continuing to the anterior 
end of the limb. The lower margin runs in a slightly concave arch from the lower corner of 
the posterior limb in an upward and forward direction. Otherwise, as far as one can 
see, the pterygoid is distinguished by the thin nature of its bone substance ;(text fig. 37) 
Sassenia tuberculata 11. sp. 
Portions of the cranial roof, cheek 
plates and visceral skeleton. The sculp¬ 
ture not drawn. From P. 22S. */=• ■ 
Mptg, metapterygoid; Op, opercular; 
Pa. it, parieto-intertemporal; Po, post¬ 
orbital; Pop. quj?, possibly a part of 
the preoperculo-quadrato/ugal; Pt, ptery¬ 
goid; Sq, pop, squamoso-preopercular; 
Stemp. ext, supratemporo-extras'capular; 
a, accessory plate originally belonging 
to the squamoso-preopercular; jc, jugal 
