Dr. R. S. Traquair — On the Genus MegalicMJujs. 115 



Fig. 3, 3a. Nerincea cingenda, Phil. Dogger, Blue Wyke. Leckenby Collection. 

 ,, 4, 4«. Nerincea cingenda, Phil. Same locaKty and Collection. 

 ,, 5, ba. Nerincea cingenda. Young specimen. Dogger, Blue "Wyke. York 



Museum. 

 ,, 6, 6«. Nerincea. Dogger, Blue Wyke. Leckenby Collection. 

 ,, 7. Nerincea. "Whitwell Oolite. York Museum. 

 ,, 8. Nerincea, Millepore Rock, Cloughton. flerries Collection. 

 ,, 9, 9a. Nerincea cingenda, So'iv. Dogger, Blue Wyke. Leckenby Collection, 

 ,, 10, 10a. Nerincea '■'fasciata, Voltz." Cornbrash, Scarborough. Leckenby 



Collection. 



{To be continued.) 



IV. PlBMARKS ON THE GkNUS MeGALICHTHTS, AgASSIZ, WITH 



Description of a New Species. 



By Dr. E. H. Traquair, F.R.S., F.G.S. 



(PLATE V.) 



THERE can be no doubt that the name Megalichthys was originally 

 suggested to Agassiz by the gigantic teeth of the great round- 

 scaled fish first brought into notice by the researches of Dr. Hibbert, 

 in the quarries of Burdiehouse, though indeed some of its remains 

 had long previously been figured by Ure in his " History of 

 Eutherglen and East Kilbride." Incontrovertible evidence of this 

 may be found by referring to the Proceedings of the British Asso- 

 ciation for 1834, and to Dr. Hibbert's original memoir on the 

 Burdiehouse Limestone published in the Transactions of the Eoyal 

 Society of Edinburgh, vol. xiii. 1835. But with the remains of this 

 enormous creature were also associated and confounded certain 

 rhombic glistening scales, belonging really to a considerably smaller 

 fish of a totally different genus, and when Agassiz, subsequently to 

 the meeting of the British Association at Edinburgh in the j^ear 

 above quoted, found in the Museum at Leeds a head of this latter 

 form, or at least of an allied species, he adopted it, by description 

 and by figure, as the type of bis Megalichthys Uihherti,^ relegating the 

 other to the genus Holoptychius. This latter, the real " big fish," is 

 now known as Rhizodus Hibberti, the founder of the genus being 

 Prof. Owen; and though it may be a matter of regret that it did not 

 retain the name Megalichthys, the laws of zoological nomenclature do 

 not admit of any alteration now. 



The brilliantly enamelled scales, head-plates, and teeth of Megal- 

 ichthys are among the commonest vertebrate remains found in the 

 estuarine beds of the Carboniferous epoch in Great Britain ; never- 

 theless, specimens showing the fish itself in any but a very fragmentary 

 state are rare, and though the head is very well known, from the 

 magnificent specimen at Leeds figured by Agassiz, no concise 

 desciiption of the configuration of the body or of the arrangement 

 of the fins has yet been given. It was classed by Agassiz in his 

 hetei-ogeneous group of " Sauroides," but the resemblance of its 

 scales and head-plates to those of the Old Eed Sandstone genera 

 Osteolepis and Diplopterus did not escape the attention of Sir Philip 



1 Poissons Foss. vol. ii. pt. 2, pp. 89-96, pi. 63, 63a, and 64. 



