CRANIA. 49 



suppose that the typical shape of lamellosa does not occur in England, as examples identical 

 with some represented in Geinitz's Versteinerungen have been found at Dalton. 1 



Loc. Strophalosia lamellosa or Morrisiana has been found by Professor King, 

 Messrs. Howse, Kirkby, and others, in the shell and compact limestone of Humbleton and 

 Tunstall hills, Ryhope-field House, Weston, Dalton-le-Dale, Clack's Heugh, &c. A very 

 remarkable specimen has also been found by a gentleman in the lowest beds of limestone 

 at Midderidge. The species likewise occurs in several German localities near Gera, at 

 Possneck, &c. 



Family— CRAM AD JE. 



Genus — Crania. 

 {Vide Introduction, Vol. I, p. 122.) 



Crania Kirkbyi, Davidson. 



The upper valve only of this shell has been discovered. It is sub-quadrate, with rounded 

 angles, and is sometimes a little indented at its anterior margin : is slightly conical, 

 with a sub-central vertex, and presents a small longitudinal depression on 

 its anterior portion. Externally the entire surface is closely covered by a 

 multitude of minute, short, hollow, spinulose tubercles, which produce a 

 granulated aspect. The interior was not completely exposed in the specimens ; but the 



impressions may be modified bases of abortive spines. I am not aware that this species has been found 

 anywhere except at Tunstall hill. ****** 



" Var. H umbletonensis . General form rather strougly convex, as wide as long, sometimes longer thaw 

 wide, rarely the converse. Large valve rather strongly convex, and evenly rounded ; occasionally with one 

 or more longitudinal wrinkles on the sides ; furnished with numerous long, somewhat irregularly arranged 

 spines, creeping, and directed forward on the back, erect, and bent backwards on the sides and adjacent to 

 the hinge; both inner and (!) outer surface marked with numerous fine striae, radiating from the umbone, 

 also with well-defined incremental lines ; umbone somewhat tumid, occasionally a little impressed, and 

 incurving over or below the cardinal edge ; area small, scarcely perceptible through the incurvation of the 

 umbone; teeth well developed. Small valve slightly concave, marked with numerous elongated, indented 

 impressions, which are somewhat regularly arranged, and deepest at their anterior end; both inner and 

 outer surface marked with distinct radiating striae ; those on the sides near the hinge dichotomous, and 

 arcuated or curving posteriorly ; they pass uninterruptedly over the indented impressions, and are crossed 

 by rather strong incremental lines. Nucleus raised a little above the general surface of the valve." 



1 Dr. Geinitz has also declared (in a letter to Professor King, dated Dresden, the 1 1th of March, 1857) 

 that his St. lamellosa is distinct from King's Morrisiana, but he has also confounded this last with 

 Productus Cancrini, and is evidently not well acquainted with the numerous forms and variations presented 

 by his lamellosa in England, 



7 



