678 REPORT— 1888. 



author specified the vertebral characters which should be observed, as size, number 

 in the several regions, proportions of centrum in each region, proportions of vertebrae 

 to limb bones and to the skull. 



5. A Comparison of the Cretaceous Fish-fauna of Mount Lebanon with that of 

 the English Chalk. By A. Smith Woodward, F.G.S., F.Z.8. 



No detailed comparison having hitherto been instituted between the Cretaceous 

 fish-fauna of Mount Lebanon and that of the English chalk, which belongs to a 

 well-determined horizon, the author has undertaken a general survey of the genera, 

 with the result that the two faunas are proved to have more forms in common than 

 hitherto supposed. The Selachian fishes are scarcely comparable, Notidanus and 

 Squatina being the only genera as yet recognised in the two formations, although the 

 English teeth named Lamna rhaphiodon seem to belong to the shark named Rhi- 

 nognathus ; on the whole, those of Mount Lebanon exhibit the most modern facies, 

 all traces of Hybodont Sharks and of PtycJwdus being wanting. Chimseroids are 

 unknown at Mount Lebanon, but abundantly met with in the English Chalk. 

 Among Ganoids there are representatives of the Pycnodonts both in the Lebanon 

 {Palesobalistum, Coccodus, Xfnojj/iolis) and in England (Coilodus), but no identical 

 genera can yet be recognised. Rhombic-scaled Ganoids are rare in the English 

 Chalk {Lojykiostomus, Acorhombolepis), and unknown in ilount Lebanon ; traces of 

 Acipenseroids also occur in the former, but have not been discovered in the latter ; 

 and at least one Crossopterygian genus occurs plentifully in England {AIac7-opo7na), 

 while no uncertain remains have been detected in the Syrian beds. Bdonostoimis, 

 however, is common to the two formations, one species having been described from 

 Mount Lebanon under the name of Rhinellus hiniatus. 



Of Physostomous Teleosteans, the great early families represented in the Chalk 

 of England and the Upper Cretaceous of North America by Portheus, Ichthyodec- 

 tes, Proiosphyr(V7ia and Pachi/rhizodus, are quite unknown in the deposits of Mount 

 Lebanon ; but in the latter locality Enchodus is abundant, having been described 

 under the s3^lonym of Ewygnathus, and this is accompanied by a closely-allied 

 genus, Eurypholis, only differing in the possession ot a few dermal scutes. The 

 English Pomopiathus may also be regarded as represented at Mount Lebanon, for 

 the so-called Phylactocephalus merely difters in the presence of extremely delicate 

 minute scales, which would not be preserved in a matrix of the nature of the 

 Chalk ; and Aqjidopleurus (Mount Lebanon) possesses scutes indistinguishable 

 from the detached examples long known in the English Chalk under the name of 

 Prionolepis. Dercetis, also, is met with abundantly in the Syrian beds, being 

 described under the .synonym of Lepfofrachclus. Among Elopine Clupeoids, some 

 undescribed forms occur in the English Chalk, and one from Mount Lebanon has 

 been erroneously assigned to the genus Clupea (' C. Lewisii ') ; and the supposed 

 Salmonoid, Osmeroides, is common to the two formations, though inferior in size at 

 the last-named locality. In the Syrian deposits, however, there are many more 

 specialised Physostomi, such as Cheirothrix, Spaniodon, Opisfopferi/.i, Rhinellus, 

 Sco7nbroclupea, Diplomystus, and Clupea, of which no traces appear to be discover- 

 able in collections of English Chalk fossils. Among Physoclystous Teleosteans but 

 few genera are common to the two formations under comparison, Hoplopteryx, 

 with perhaps Beryx, represents the BerycidiB in both localities ; but only a single 

 imperfect specimen from the English Chalk can yet be assigned to any higher type, 

 namely, Platax (?) nuchalis. At Mount Lebanon more specialised Physoclysti are 

 numerous, as Platax, Imoyasfer, and Pycnosterinx ; although to the latter have been 

 erroneously assigned certain extraneous forms, including at least one well-marked 

 Berycoid, the so-called Pycnosterinx Lewisii. 



The conclusion is thus arrived at, that in those respects in which the Lebanon 

 fish-fauna differs from that of the English Chalk, it exhibits greater specialisation. 

 Considered alone, therefore, it is distinctly of a more modern type than the latter, 

 although the beds in which it occurs are regarded, from other evidence, as being of 

 Turonian age. 



