GREY CHALK MARL. 119 



crenated by the angular terminations of the plicee; aperture slightly 

 sagittate ; siphunculus ? 



The longest diameter is about 8 inches, greatest thickness 1*8 inch, 

 width of the outer volution 5 inches. 



The volutions are thickest near the middle, and gradually contract 

 into a narrow keel, which at the aperture, does not exceed 0-4 inch in 

 width, and has an elevation or ridge down the centre. The pUcee are 

 small, and extend from the outer margin over one-third of the wreath, 

 but the intermediate ones do not reach beyond half that distance : their 

 terminations are angular, and form a crenated border on each side the 

 keel. 



This species may be distinguished by its flatness, the great width of 

 the outer volution, the small conical umbilicus, the narrow keel, and the 

 angular plicae. 



The septa are numerous, and very foliaceous. 



LocaUty. Hamsey. 



35. Scaphites striatus. Tab. xxii. figs. 3, 4, 9, 11, IS, 14, 15, 16. 



Volutions transversely striated; striae numerous, obhque, annular, bi- 

 furcate; dorsum tumid; aperture produced, transversely ovate, marginate ; 

 siphunculus internal? 



This species is commonly about an inch in length, the greatest thick- 

 ness is 0-4 inch, width 0-8 inch. The inner whorls are umbiHcate, deeply 

 inserted, and wholly concealed by the outer volutions. The dorsum is 

 suddenly enlarged, and the reflected turn terminates before it reaches the 

 centre. The aperture is entire, of an irregular ovate form ; the margin 

 jDrominent, the upper part produced, extending a httle over the spire. 

 The whole shell is striated; the striee arise singly from the inner margin, 

 and dividing into two or three, pass over the dorsum, and unite with the 

 corresponding ones of the opposite side. The inner half of the outer vo- 

 lution is somewhat depressed, and from thence the stria extend obliquely 

 in a radiating manner, and bifurcate at the edge of the depression ; to- 

 wards the aperture of the shell, the striae are larger and more distinct. 

 The septa are but slightly concave, and their edges have three principal 



