from the Neighbourhood of Edinburgh. 263 
orbit seems to have been well forward, as in the last-named 
genus. In Pl. XVI. fig. 2 1 have indicated in diagrammatic 
outline the various bones which may be distinctly made out. 
Behind we have a pair of parietals (p), in front of which are 
the more elongated frontals, of which the impression of the right 
one (f) is seen; on the outer side of the parietal is a plate (sq), 
which answers to the sguamosal, in frontof which, and external 
to the frontal, is another (p.f) which may be reckoned as the post- 
frontal. The bones of the ethmoidal region, forming the short 
rounded snout, are too much crushed for description. All these 
cranial bones, as shown by their impressions, were ornamented 
by beautiful branching and anastomosing flexuous ridges ; the 
impressions of their internal surfaces, shown by removing the 
friable bone from the other half of the specimen, display lines 
radiating from the ossific centres ; and here also a groove, tra- 
versing longitudinally the frontal and parietal, betrays the 
course of the usual slime-canal. Very little is seen of the facial 
bones. A portion of the hyomandibular (h.m) is seen passing 
downwards and slightly backwards from under the squamosal, 
and seems to have been arather slender bone like that of Pale- 
oniscus. ‘The operculum (op) is shaped much like that of 
Mesolepis, being four-sided, rather higher than broad, and with 
round posterior-superior and posterior-inferior angles; it is 
evidently displaced somewhat upwards and backwards. Below 
it is the suboperculum (s.op), also displaced and apparently 
a little turned round, so that what I conceive to be its upper 
margin comes in fact to look as much forwards as upwards. 
The only other recognizable facial bone is the maxilla (mx), 
a plate of considerable size, gently convex externally and 
broader behind than in front; its external surface was orna- 
mented by wavy ridges very similar to those on the cranial 
bones. ‘The lower jaw and branchiostegal rays are, unfortu- 
nately, not discoverable, nor have I been able to detect any 
trace of teeth. 
Shoulder-girdle.—The first supraclavicular (suprascapular, 
Owen) is a very large, nearly square-shaped plate (1s¢ s.c/), 
which is placed behind the parietal, and is apparently in con- 
tact at the middle line with its fellow of the opposite side. By 
its lower margin it articulates with the second supraclavicular 
(scapular, Owen), also of considerable size. This bone (2nd 
s.cl) is vertically oblong in form, rather broad above, where it 
is obliquely traversed by the lateral slime-canal before that tube 
enters the scales of the lateral line, and narrowing down to a 
point below. I exposed the whole of it by sacrificing and 
chiselling off the operculum (which covered a large part of it), 
as the whole contour of the last-mentioned bone is so well seen 
