Stnccture of the Lower Jaw in Kliizodopsis aind Bhizodus. 135 



Wednesday, list February 1877.— Dr Kamsay H. Tkaquaib, F.G.S., 

 President, in tlie Chair. 



The following donations to the Library were laid on the table, and thanks 

 voted to the donors : 



1. Videnskabelige Meddelser fra Naturhistorisk Forening i Kjobenhavn, 

 for Aaret 1875. — From the Society. 2. Oversigt over det Kongelige Danske 

 Videnskabernes Selskabs Forliandlinger og dets Medlemmers Ai-bijder — 

 1875, Nos. 2, 3 ; 1876, No. 1.— From the Society. 3. Acta Horti Petro- 

 politani, Tomus IV., Fasciculi 1, 2 ; cum Suppl. ad. IV. — From the Imperial 

 Botanic Garden, St Petersburg. 4. The Canadian Journal of Science, 

 Literature, and History, Vol. 15, No. 4; January 1877.— From the Canadian 

 Institute, Toronto. 5. Proceedings of the Koyal Society (of London), Vol. 

 25, No. 175 (Nov. 1876). — From the Society. 6. Journal of the Linnean 

 Society— Botany, Vol. 15, No. 87; Zoology, Vol. 13, No. 66.— From the 

 Society, 7. Proceedings of the Geologists' Association (London), Vol. 4, No. 9 

 (Oct. 1876).— From the Society. 



The following communications were read : 



I. 071 the Structure of the Loiuer Javj in Eliizodopsis omcI 

 Ehizodiis. By Eamsay H. Teaquair, M.D. 



Among the detached and broken- up remains of the Coal- 

 measure fish known as BMzodopsis sauroides, one of the most 

 frequently observed is a bone of a somewhat narrow and 

 elongated form, truncated and somewhat expanded at one 

 extremity, which may be assumed to be the anterior, and 

 pointed at the other or posterior. One margin, nearly straight, 

 save just in front, where it shows a slight convexity, is set 

 with a single row of small pointed teeth of nearly uniform 

 size ; but the anterior extremity bears in addition a single 

 more or less incurved laniary tooth, much larger than the 

 others, and also more internal in its position ; the opposite 

 margin, thin and sharp, displays a gently flexuous contour. 

 Seen from, the inner aspect, the anterior extremity of the bone 

 presents a conspicuous thickening, in wliich the large laniary 

 is socketed, and which at the dental margin passes into a 

 delicate ledge, which runs back for some distance along the 

 roots of the smaller teeth. 



This bone, whose external form has been well described by 

 Messrs Hancock and Atthey,* was considered by them to be 

 the jprcemaxilla of Ehizodopsis, being obviously distinct from 



* Ann. & Mag. Nag. Hist. 1868, ser. 4, vol. i., pp. 350, 351= 



