THE 



GEOLOGICAL MAGAZINE. 



No. XC— DECEMBER, 1871. 



oi^ia-i3:<T.A.L J^I^Tzo^L:E]S. 



I. — Notes on the Genus Phaneropleuron (Huxley), with a 

 Dbsckiption of a New Species feom the Carboniferous 

 Formation. 



By Eamsay H. Traquair, M.D., 

 Professor of Zoology in the Eoyal College of Science, Dublin. 



(PLATE XIV.) 



THE genus Phaneropleuron was instituted by Professor Huxley, in 

 1859,^ for the reception of that singular fish P. Andersoni, from 

 the Upper Devonian Yellow Sandstone of Dura Den, in Fifeshire, 

 which species was also subsequently described by him in the tenth 

 Decade of the Geological Survey, published in 1861. In the present 

 communication I have to add a second species, from the Lower 

 Carboniferous strata (Burdiehouse Limestone) of Edinburghshire, 

 by which our knowledge of the genus is thus certainly carried a 

 stage further upwards in the geological series. 



Before, however, proceeding to the special description of the 

 Carboniferous form, I have a few notes to contribute regarding the 

 general characters of Phaneropleuron, as shown in the first described 

 species, the results of a careful examination of the specimens in the 

 St. Andrew's Museum, obtained subsequently to the publication of 

 Professor Huxley's descriptions. I have also enjoyed the oppor- 

 tunity of comparing these results with the appearances exhibited in 

 the suite of specimens in the British Museum, and in the Museum of 

 Practical Geology in Jermyn Street. 



As Professor Huxley has pointed out, in his excellent and concise 

 descriptions above referred to, Phaneropleuron Andersoni is remark- 

 able for its thin circular overlapping scales, for its persistent noto- 

 chord, but well ossified neural and hasmal arches, spines, and median 

 fin-supports, and for the great length and prominence of the ribs, 

 which shine so conspicuously through the thin external covering of 

 scales. The ventral, and most probably also the pectoral fins, are 

 acutely lobate, with a central scaly axis fringed with rays on both 

 sides, as in the recent Ceratodus Forsteri, the extinct Holoptychius, 

 etc., and there is a distinct narrow anal fin in front of the lower lobe 



1 In Anderson's " Dura Den, a Monograph of the Yellow Sandstone." Edinburgh, 

 1859. 



VOL. VIII. — NO. XC. 34 



