voxciiOLOay. 140 



The Xatiras freqnont sandy p-ound, along whicli they creep quickly, or in which 

 they btirrow in pursuit of bivalves, wliicli constitute their food, whose shells they 

 drill with their tongue, and then extract the contents by means of their long retractile 

 proboscis. 



*Xatica globosa, Phil. 



'' ,, rKI.LISTUIOIU.N.l, Kust. 



* ,, CiiEMNTrzn, Uceve. 



* ,, MAMMII.LATA, LaUl. 



* ,, LixEATA, Lam. 



* ,, AKACn.NOIDF.A, Gmcl. 



* ,, MKLAXOSTOMA, GlUel. 



* ,, AxTONi, rhil. 



* ,, Zaxzeiiakica, Reeve. 



* ,, zosAiuA, Lam. 



* ,, Tj;xiATA, Phil. 



* ,, simi.t; ('?), Reeve. 



* ,, GALACTITES, Phil. 



Mamma, Klein. 



Operculum horny. Shell solid, smooth, with inner lip oblique, thickened. 

 Columella spirally twisted. Apex more or less dilated and convex. When the 

 auimal crawls, the hind lobe of the foot nearly covers the shell. 



Mamma ALiin.A, Runiph. Andamans. 



,, MAMMILLA, L. Audamaus. 



Catixus, Klein. 



Operculigerous lobe very large, almost concealing the slu'll. Operculum very 

 small and rudimentary. 



The Catini arc sluggish and ^■ery timid, ciawling on mud flats, and exploring the 

 ground with the produced fore-lobe of the foot. 



*Catixcs Delesseuti, Eecluz. 

 (/tisctis, Morch.) 



* „ I'LAxus, Reeve. 



Finn ill) Cassididse. 



Teeth, many rows of lancet-shaped ones, and one denticulated row in the centre. 

 Siphon recurved. Foot large, dilated. Operculum annular, nucleus in the middle 

 of the straight inner edge. Shell ventricosc, apeiture with a recurved canal, outer 

 lip thickened, inner lip wrinkled or granular. The Cassidte or ' Helmets ' are active 

 aud voracious, preying on bivalves. The shells of the larger species are used in the 

 manufacture of ' cameos.' 

 *Semicassis aeeola, L. 



* ,, GLAUCA, L. 



* ,, BIAKMATA, DiUwyU. 



S. torquata, Reeve. 



* ,, EKINACEUS, BrUg. 



*Cassidea tibex, L. 



Family Scalariidae. 



Teeth in transverse rows, with no median series. Mantle with a rudimentary 

 siphonal fold. Poot obtusely triangular, grooved lielow, and furnished in front with 

 a fold. Operculum horny, paucispiral. Animal prcdaceous. Shells white, and 

 remarkable for their elegant sculpture. 



*ScALAKiA trilineata, Dc Haon. 



* „ (like a dwarf communis). 



