420 . Mr. J. Lycett on Fossil Shells from the 



carinse and large digital processes ; caudal extremity slender and 

 lengthened ; the slender form, crenulated carina and smooth surface 

 distinguish it from R. trifida. Portions and casts of two other spe- 

 cies of RostellaricB have been obtained, but not sufficiently perfect to 

 admit of being described. 



107. Serpula IcBvigata; a simple, round, smooth spiral tube, the 

 tube being rather thick. 



101*. Fusus 1 carino-crenatus ; shell small, fusiform ; spire of four 

 volutions, keeled and striated ; an elevated carina encircles the middle 

 of each whorl, its edge undulated or crenulated ; encircling striae cover 

 the whole surface of the shell, and there is an indistinct circle of no- 

 dules upon the upper portion of each whorl near to the junction. 



127. Natica Gomondii\ small, globose; spire small; whorls con- 

 vex, narrow, their upper margins cinctured with a narrow, flat, hori- 

 zontal area, the outer edge of which is acute : rare. 



125. Lima plicata ; elongated, narrow ; costse nine, very large and 

 elevated, rounded and imbricated. 



126. Lima alata ; auricles very large, the length of the hinge-line 

 being equal to that of the longitudinal diameter ; anterior auricle 

 much folded ; ribs numerous, narrow, regular and imbricated. 



130. Lima punctatilla-, shell minute, gibbose, nearly straight; 

 costse about twenty, rounded, large ; interstitial spaces narrow ; sur- 

 face of the costse punctated where they are crossed by very fine lines. 



134*. Possibly a variety of Pecten clathratus with large, elevated 

 encircling ribs. 



130*. Lima minutissima -, oblique, broad, convex; costse fourteen, 

 rounded, smooth, wider than the interstitial spaces, nearly evanescent 

 upon the anterior side. 



137. Pecten lineolatus ; auricles large, striated ; shell ovate, slightly 

 convex ; costse very minute, numerous, waved and granulated, dege- 

 nerating into very fine lines towards the ventral border, and crossed by 

 encircling lines, very fine, and arranged in the closest possible order. 



138. Hinnites sepultus -, suborbicular, rather irregular, convex; 

 auricles unequal ; costse ten, equal, radiating, waved, small and cre- 

 nulated, degenerating towards the ventral border into mere lines ; in- 

 terstitial spaces wide, each having one or two longitudinal lines ; 

 length J inch. 



141. Plicatula elongata; elongated, rather oblique ; costae longi- 

 tudinal, waved, very fine, closely arranged, rounded and scabrous, 

 terminating towards the tubular border in a few tubular spines. 



143. Placuna armata ; the normal form is that of curved radiating 

 lines of tubular spines little elevated, but the general aspect is that of 

 irregular elevated confused tubercles. This species is placed under 

 Placuna merely to indicate that generically it agrees with the shell 

 called Placuna jurensis, but which certainly is neither a Placuna nor 

 yet an Anemia, to which latter genus it has sometimes been assigned ; 

 its true place must remain for the present in abeyance. 



144. Placuna 1 complicata; surface covered with clusters of tu- 

 bular spines, depressed and confused, producing a most irregular and 

 uneven surface. 



