from the Neighbourhood of Edinburgh. 263 



orbit seems to liave been well forward, as in the last-named 

 genus. In PI. XVI. fig. 2 1 have indicated in diagrammatic 

 outline the various bones which may be distinctly made out. 

 Behind we have a pair oi parietals (^?), in front of which are 

 the more elongatcd/z-o/j^rt/A', 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 squamosal , in front of which, and external 

 to the frontal, is another {-pf) which may be reckoned as the^os^- 

 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 tlieir internal surfaces, shown by removing the 

 friable bone from the otlier half of the specimen, display lines 

 radiating from the ossific centres ; and here also a gi-oove, 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.rn) is seen passing 

 downwards and slightly backwards from under the squamosal, 

 and seems to have been a rather slender bone like that of Palce- 

 oniscus. The operculum [op) is shaped much like that of 

 MesolepiSj 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 suhoperculum (s.op), also displaced and apparently 

 a little turned round, so that wdiat I conceive to be its upper 

 margin comes in fact to look as much foi-wards 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 jaAV and branchiostegal rays are, unfortu- 

 nately, not discoverable, nor have I been able to detect any 

 trace of teeth. 



Shoxilder-girdle. — The first supraclavicular [suprascapular ^ 

 Owen) is a very large, nearly square-shaped plate {1st s.cl), 

 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 

 (scapidar, Owen), also of considerable size. This bone {2nd 

 s.cl) is vertically oblong in form, rather broad above, where it 

 is obliquely ti-aversed 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 



