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OSTEOSTRACI. 



are less produced and less divergent than in the English heads." A 

 Glammis specimen mentioned below (No. P. 3234) apparently rend- 

 ering this conclusion unjustifiable, we venture to revert to Agassiz's 



Cephalaspis lyclli, kg. — Side view, restored by Lankester. [The opercular fold 

 is too distinctly separated from tbe shield, having the appearance of a 

 pectoral appendage.] 



original arrangement, and regard the differences as due to accident 

 in preservation. 



20087. Type specimen, described and figured by Agassiz (p. 143, 

 pi. i. a. fig. 2) and Lankester (p. 44, pi. viii. fig. 1) ; 

 Glammis, Forfarshire. Since the original description of 

 the specimen by Agassiz, the squamation of the caudal 

 region has been more completely extricated from the 

 matrix ; and during this process the greater part of the 

 opercular fold of each side was accidentally destroyed. 



Presented by Sir Charles Lyell, Bart., 1846. 



P. 3233. Portions of head and trunk of a similar specimen ; Glammis. 



Enniskillen Coll. 



P. 3234. Small shield, much crushed and broken, labelled C. agassizi 

 by Mr. William Davies, and agreeing in every respect with 

 the definition of this supposed distinct species ; Glammis. 

 The portion of shield in advance of the anterior margin of 

 the orbits measures 0*015 in length, that behind 0*02. 



Enniskillen Coll. 



42140. Fragments and internal impression of shield ; Cradley, 

 Herefordshire. Baugh Coll. 



P. 3235. Small shield, scarcely crushed, but wanting the external 

 layers ; Cradley. Enniskillen Coll. 



36052. Portion of a similar specimen ; Cradley or Ludlow. 



Purchased, 1861. 



45945-47, 47 a. Four imperfect shields ; Whitbatch, near Ludlow 



Lightbody Beqiicst. 



