App. a. 3 Dr. FiTTON on the Strata below the Chalk. 343 



Fig. 2. Terehratula dilatata. Wider than long, depressed, imperfectly three-lobed; plaited, 

 plaits about 50, sharp ; central lobe elevated ; beak of the larger valve short and large. This 

 resembles Terehratula FespertUio of Brocchi, but is not so wide nor so distinctly three-lobed. 



Fig. 3. 2'erehratula megatrema ?. Moderately convex, transversely obovate ; with a few 

 distinct ribs. The beak is large and produced, with a very large perforation : whence the name. 



Fig. 4. Dentalium medium. (An inferior figure is in Min. Conch, t. 79.) Subulate, very 

 slightly curved, striated ; striae sharp, elevated, alternately smaller, gradually disappearing towards 

 the aperture. 



Fig. 5, Litorina pungens. Conical, acute, smooth; whorls five or six, the last inflated; 

 aperture orbicular, with a projecting angle above ; columella slightly compressed. This species, 

 probably, belongs to a group of shells which Lamarck has called Ampullaria; and which in the 

 Mineral Conchology is referred to Natica, but in the Index to that work is named Globulus. 

 The columella is, however, rather different. 



Fig. 6. Natica canaliculata. Species the same as PI. XI. fig. 12, but a much larger specimen. 



Fig. 7. Natica granosa. Subglobose ; spire prominent, pointed, small ; covered with spiral 

 ridges which are divided by the lines of growth into rounded granules ; whorls very convex ; 

 aperture oblong, expanded ; umbilicus open. 



Fig. 8. Natical carinata. Oblong, with a small distinct spire ; surface marked with five pro^ 

 minent rugged keels ; aperture large. This shell appears to be umbilicated, but is not perfect ; 

 hence the genus is doubtful. 



Fig. 9. Tornatella affinis. Ovate, pointed ; base truncated ; surface grooved, grooves 

 crossed by lines ; columella with one simple and one double fold. Very like Acteon {Tornatella) 

 simulatus of the London clay, (Min. Conch, tab. 163. fig. 5. to 8.) but more elongated, more 

 acute, and smaller ; yet shorter than Tornatella elongata, (tab. 11. fig. 1.), 



Fig. 10. Vermetus concavus. (Min. Conch, t. 57. fig. l.to 5.) Tube rounded, curved into a 

 depressed spiral, which is concave beneath ; the whorls united by an expansion of the shell from 

 the sides. These figures show the prolongation of the tube beyond the spiral part, which is not 

 shown in the Mineral Conchology. 



Fig. 1 1 . Scalaria pulchra. An acute shell, with blunt costae ; whorls ten, close : a band con- 

 nectuig the costae passes along the bases of the whorls. 



Fig. 12. Littorina gracilis, A pretty, elongated, acute shell, with round whorls, bearing de- 

 cussated furrows on their upper parts ; aperture round, with an angle at the base. 



Fig. 13. Phasianella pusilla. Elliptical, elongated, pointed, perfectly smooth ; aperture ellip- 

 tical, more than half as long as the shell. 



Fig. 14. Phasianella formosa. Elliptical, elongated, rather blunt ; smooth, except a few striae 

 at the base ; aperture more than half the length of the shell. 



Fig. 15. Phasianella striata. Elliptical, pointed, strongly striated ; aperture oval, above half 

 the length of the shell. This is like Phasianella princeps (Defrance), but more regularly oval. 



Fig. 16. Fusus rigidus. Fusiform, costated, transversely striated ; costae rounded, roughened 

 by the lines of growth; transverse striae prominent, about 10 upon each whorl ; whorls five or 

 six, swelled in the middle, compressed at the upper part ; aperture more than half as long as 

 the shell, elliptical, pointed at both ends ; beak variously elongated. The individuals of this 

 species differ much in length and asperity ; the edge of the aperture is frequently reflected. 



Fig. 17. Fusus quadratus. {Murex quadratus, Min. Conch, t. 4:\0, young.) Fusiform, rhom- 

 boidal, with a short conical spire, transversely striated and obscurely bicarinated ; base produced, 

 conical ; whorls about five ; aperture sub-rhomboidal. The form of the shell is fully developed 

 in the specimen here represented. 



VOL IV. — SECOND SERIES. 2y 



