244 Proceedings of the Roycd Physical Society. 



3. Rhadinichthys Grossarti, Traquair, sp. no v. 



Description. — The length of this little fish was probably 

 two inches or thereabout, but as yet no specimen has occurred 

 absolutely perfect. One specimen, wanting the head, in the 

 collection of Mr Grossart of Salsburgh, measures 1\ inch in 

 length ; two others in the collection of the Geological Survey 

 of Scotland, one of which wants the head, the other the tail, 

 measure each IJ inch. The last-named collection contains 

 also a few others still more fragmentary, but all indicating a 

 fish of about the same size. The bones of the head are, judg- 

 ing from their impressions, marked with irregular rugse ; no 

 teeth are visible. The form of the body is very slender, its 

 depth at the ventral fin being, in Mr Grossart's specimen, not 

 quite \ inch, from which it tapers to a very delicate tail 

 pedicle. The pectoral is not seen ; the ventral is small, and 

 consists of a few delicate and rather disturbed rays. The 

 dorsal commences very slightly in front of the anal, and con- 

 sists of fourteen or fifteen rays, but in the anal I count only 

 ten. Between the latter and the lower lobe of the caudal 

 there is a considerable interval, equalling nearly f inch. All 

 these fins are very delicate, with slender, distantly-articulated 

 rays ; minute fulcra are observable on the anal of one speci- 

 men; the caudal body-prolongation is very slender and 

 attenuated. The scales are moderate, may indeed be called 

 large, in proportion to the minute size of the fish. They are 

 more strongly marked than in B. monensis, their ornament 

 consisting of four to six sharply defined straight ridges extend- 

 ing from before backwards, with a slight obliquity over nearly 

 the whole exposed surface, and terminating in denticulations 

 of the posterior margin ; in some cases feeble traces of the 

 delicate vertical grooves seen in P. monensis are visible just 

 in front of the commencement of the longitudinal ridges. 



Remarks. — In its small size, and in the general form of the 

 body, R^ Grossarti resembles R. temdca^ida from the edge coal 

 strata of Scotland (middle group of Carboniferous Limestone 

 series), but it is at once distinguished from it by the sculpture 

 of the scales, which in R. tenuicauda are smooth on the flanks, 

 and only delicately striated on the dorsal and ventral margins. 



