THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 52. APRIL 1872. 



XXVI. — Descriptive Notes on a nearly entire Specimen of 

 Pleurodus Rankinii, on two new Species o/Platysomus and 

 a neiv Ampliicenti'um, with Remarks on a few other Fish- 

 remains found in the Coal-measures at Newsham. By 

 Albany "Hancock, F.L.S., and Thomas Atthey. 



[Plates XVII. & XVIIL] 

 Pleurodus Rankinii^ sp. ined., Agassiz. 



Several years have elapsed since we first obtained speci- 

 mens of the peculiar little tooth named by Agassiz Pleurodus 

 Rankinii r a few only occurred ; they were found at Cram- 

 lington. Since then several specimens of it have been pro- 

 cured at Newsham and Kenton, but never in any great abun- 

 dance. 



The tooth is, we believe, all that has been known, up to the 

 present time, of this reputed Selachian. In the spring of last 

 year (1870), however, we had the good fortune to meet with 

 the remains of an almost entire specimen of this fish at News- 

 ham, exhibiting a crushed head containing the teeth, most of 

 the body, with thoracic expansions, a dorsal spine, and the 

 shagreen covering or skin (PL XVII. fig. 1). In addition to 

 this interesting specimen, a detached head with the teeth, and 

 a separate spine, have also occurred in the same locality. 



These discoveries are highly important, inasmuch as they 

 seem to demonstrate not only that this species is a Selachian, 

 but that it is a Cestraciont, not far removed from the curious 

 Permian form Wodnika^ Miinster. This relationship is not 

 only seen in the general characters of the teeth, but also in the 

 similarity of the shagreen and in the' form and grooving of 

 the dorsal spine. 



The specimen lies apparently on its belly, and measures a 

 little more than three inches from the front of the head to the 



Ann. & Mag. N. Hist. Ser. 4. Vol. ix. 18 



