23 



AMMONITES striatulus. 



TAB. CCCCXXL— /^. 1. 



Spec. Char. Discoid, carinated, radiated ; 

 sides of the whorls convex; the inner 

 whorls exposed ; radii numerous, slender, 

 undulated; surface covered with minute 

 striae parallel to the radii ; aperture ellipti- 

 cal. 



J. HE whorls are about 6 ; their regularly convex sides, 

 and numerous, small, twice curved ribs, and slightly 

 relieved keel, give a symmetry to the general contour 

 that is not easily recollected : the diameter is nearly 

 four times the length of the aperture ; the cast differs 

 from the outer surface only in wanting the fine striae, or 

 lines of growth, from which the name is taken. 



Found imbedded in a marly Limestone nodule, accom- 

 panied with a portion of some fossil bone, on the coast 

 in Robin Hoods Bay by Mr. Crawford of Scarborough. 



AMMONITES subradiatus. 



TAB. CCCCXXl.— /^. 2. 



Spec Char. Lenticular, umbilicated, carina- 

 ted, and radiated ; radii twice curved, ob- 

 cure excepting near the margin, where they 

 are bifid ; umbilicus small ; keel entire ; 

 aperture sagittate. 



1 HE edge of this lenticular Ammonite is rather obtuse, 

 and the carina not much relieved ; the sides are nearly 

 smooth, for the curved radii are very obscure excepting 

 near the edge after they have become forked or divided, 

 as some of them are, into three or even four short ribs ; 

 the thickness is about one fifth of the diameter. 



Found several years ago on the road from Bath to 

 Bristol ; it has been broken out of a mass of the Ironshot 

 Oolite J no other specimen has reached our Cabinet. 



