122 Proceedings of the Boyal Physical Society. 



margin ; about seven or eight of tliese ridges in the space of 

 \ inch. Under surface of scale with feebly marked keel ; a 

 narrow area along the posterior margin is obliquely grooved, 

 the short grooves terminating between the denticulations of 

 the posterior margin, so as to produce a pectinated appear- 

 ance. Scales from apparently the ventral aspect are lower 

 than broad, and with more produced anterior superior angles ; 

 others, from their more regularly rhomboidal shape and 

 scanty development, or absence of the articular spine, and 

 more prominent keel of the attached surface, were probably 

 situated more towards the caudal extremity. In all cases 

 the external sculpture is similar, and the under surface dis- 

 plays the same peculiar pectinated appearance at the posterior 

 margin. 



"Associated with these scales, there is on a specimen from 

 Carluke, in the collection of Mr Grossart of Salsburgh, a 

 small fragment of the edge of what must have been a pretty 

 large jaw. This fragment is nearly 1^ inches in length, and 

 displays the stumps of five stout conical teeth, with traces of 

 smaller ones external to them ; the external surface of the 

 bone is beautifully tuberculated." 



I might also have added that the tubercles on the portion 

 of jaw referred to are, when examined under a lens, seen to 

 be ornamented with minute striae passing upwards upon them 

 from their bases. 



From the oil shale pits at West Calder and Oakbank, 

 Messrs Peach, Gibson, and Stock have collected a consider- 

 able number of specimens, which I must refer to the same 

 species. Many of these consist, like the originals upon 

 which the species was founded, only of masses of dislocated 

 scales ; there are, however, others which, though still rather 

 fragmentary, throw a considerable amount of additional light 

 upon the structure of the fish itself. All are contained in 

 ironstone nodules, save one, which was shown to me by Mr 

 Lumsden at the West Calder Oil Works, in which the scales 

 are found imbedded in a portion of the oil shale itself. 



Between the scales of the West Calder and Oakbank 

 specimens, and those forming the original types of E. pecti- 

 natus, I can see no essential difference either in configuration 



