51G 



EEV. E. B. WATSOK 0>" WEBB's 



the London-Clay fossil Platemys BullocM, and in the Pleuro- 

 sternon from the Purbeck limestone, these elements extend right 

 across the plastron, so as to entirely separate the hyosternal from 

 the hyposternal bones." — H. G. Seelet. 



Diagrammatic sketch, about natural size, to illustrate the condition of the 

 plastron in the embryonic specimen of Emyda dura above described. 1 to 0, 

 the six separate ossific pieces of one side, the second counting but one on both 

 sides, = 11 in all ; 3 and 4, the double bony centres of the hyoplastron vmited 

 by (*) a cartilaginous element, ultimately forming an ossiflc union between the 

 parts in question ; 5 and 6, bypoplastron ; u, umbilicus ; d, depression on the 

 general surface of (he plastron. 



Notes on Lowe's MS. List of Webb's Type Shells from tbe 

 Canaries (1829), and on the Annotations thereon of D'Orbigny 

 (1839), and Lowe (1860). By the Eev. E. BooG Watson, 

 F.E.S.E. & F.G.S. Communicated by J. Gtwyn Jeffreys, 

 Esq., Treas.L.S. 



[Eead April 6, 1876.] 



In the year 1829 Mr. Webb sent to Mr. Lowe, in Madeira, vari- 

 ous sea-shells which he had got in the Canaries. 



Some ten years later the whole of the fuller material accumu- 

 lated by Mr. Webb and by M. Berthelot were published under 

 the title ' Mollusques, &c. &c., recueillis aux ties Canaries, par 

 MM. Webb et Berthelot, et d^crits par Alcide d'Orbigny.' 



In this work M. d'Orbigny refers more than once to unique 



