56 MALACOZOA. GASTEROPODA. PECTINIBRANCHIATA. 



turns ; the aperture oblong, very narrow behind. 

 Politus, polished. 



4. Eulima subuldta. Shell very elongated-turrite, 

 tapering to a fine point, of about ten flat, smooth, very 

 glossy turns, which are white with two brown bands ; 

 the aperture oblong, very narrow behind. Subuldtus, 

 slender and tapering. 



GENUS 7. LACUNA. Shell ovato-conical, thin, with a 

 delicate epidermis ; the aperture oval or roundish, the 

 peristome incomplete behind, the columella flattened, 

 and forming a deep groove, continued from the umbilicus. 

 Lacuna, a furrow, trench, or hollow. Turton. 



1. Lacuna vincta. Shell ovate, conical, thin, semi- 

 transparent, with a delicate epidermis, the whorls five, 

 variously coloured, convex, the last somewhat angulate, 

 obsoletely striated transversely, with minute undulated 

 longitudinal striube ; the aperture roundish-ovate, the 

 columellar groove curved, narrow. Finctus, girt. 



A. L. vincta quadrifascidta. Four-banded. 



B. L. vincta bifascidta. Two-banded. 



C. L. vincta unicolor. Of one colour. 



2. Lacuna fascidta. Shell subglobose, broader than 

 long, with the spire depressed, the turns three, very thin, 

 transparent, the last extremely large, with four white 

 and three reddish-brown bands. Fascidtus, banded. 



3. Lacuna pallidula. Shell semiovato-globose, sub- 

 conical, thin, of four turns, with the spire very short, 

 and having the margin of the turns sloping towards the 

 suture, the aperture extremely large, the inner lip ex- 

 tended somewhat in the manner of that of a Nerita. 

 Pallidulus, diminutive of pallidus, pale-coloured. 



4. Lacuna sulcdta. Shell subglobose, broader than 

 long, rather thin, of three and a-half turns, marked with 

 oblique growth-lines at intervals, the spire very short, the 

 aperture semicircular, extremely large, the inner lip 

 nearly straight, with a very wide umbilical groove. Sul- 

 cdtus y grooved. 



GENUS 8. RISSOA. Shell conical, with the spire elon- 



