STYRACOPTERUS FULCRATUS. 1S3 



Specific Characters. — Scales very similar in shape, proportions, and markings to 

 those of Holurus Parkin but no denticulations visible on the posterior margins even 

 of the most anteriorly situated flank-scales. A row of pointed imbricating azygous 

 scales extends along the middle line of the back, from the head to the dorsal fin, and 

 these are much stronger and with fewer and coarser ridges than in Holurus Parki. At 

 the commencement of the dorsal fin, these median scales pass into a few large and 

 prominent fulcra placed along its anterior margin; the rest of the fin is conformed as in 

 Holurus Parki, extending, as in it, to the commencement of the tail pedicle, but the 

 transverse articulations of the rays seem a little more distant. Anteriorly, the impressions 

 of a few similar fulcra are seen adpressed to the body, as if they had belonged to the 

 pectoral. 



Observations. — The type specimen, in the collection of the Geological Survey of 

 Scotland, shows the greater part of the body with the dorsal margin and dorsal fin, but 

 it is deficient in the head, the ventral margin, and the other fins. Finer specimens have 

 since been obtained by the same Survey. 



Geological Position and Locality. — Lower Carboniferous (Calciferous Sandstone), 

 Tarras Foot, Eskdale, Dumfriesshire. 



