li? PHRONTIS. 



X. CRASSA. Koch. PI. 1/5. t'm's. ISX-iOO. 



Yellowish or irreyish, witli usually a superior white band. 

 Yery thick, rilis rather small, broken into i>T:inule*. 



Length, '(>-'~~\ inch. 



(.'Jn'iKi, Viti Ifil.ex. 



Fiir. 1X8 is a copy of the type, said to conic from China, hut 

 that locality is doubtful : the more usual form of the species is 

 that of 1ii>-. ISO. A', xf.iit'ixulrvfft.. Hombr. et Jacq. (lisr. '1 0(1). is a 

 synonym. The specie* is remarkable lor 1 he ponderous thick- 

 ness of well-uTown individuals. 



X. MK;A, 15ni<r. PI. i:J. lio- s . 191-1!):}. 



Obliquely costate, costa- sio-moid, with close revolving stria- 

 which are fVe(|iiently obsolete on the body whorl except its 

 lower part. Ye.Jlowish or orange-red, banded: or sometimes 

 pfirti-colored on the body whorl, the lower portion beino- darkej-. 



Len11i, '5-' 7 inch. 



West Africa. 



Fio-. I()L J represents an elongated variety, and (i^. 1 0;> is X. 

 <>hli<jHi>j>l /<(//<! . I) linker. 



X. AMBIOUA, Afont. PI. 1:-}. tio-s. 104-107. LM:-J. 



XarroAvly shouldered, ribs ]>retty elose. crossed ;ts wcii as the 

 interstices by line revol vini> - lines. White or yellowish, o-ciierally 

 hnndecl. spotted or maculated with brown. Length. '4 -'.">;"> inch. 

 Wist Indie*, \Ve*f (Jotint of Africa. - Dunker. 



First described by Montajrn as a British species, and occa- 

 sionally found on the western shores of Europe, but its 

 occurrence is Adventitious. Its more scalariform spire, finer 

 sculpture, color, absence of the strong nodules, and narrow. 

 defined columella callus will serve to distinguish it from A', 

 r/fo'.r. Say. The synonyms are X. Anlilld.rinti (I'm'. 104). N. 

 Candei. (fijr. 10.")) and X. //o/<>.-/,</-/ (lio-. MM;), all of d'Orb.. and 

 all immature shells, of different . ftges ; and A', at-uta. Say (li<j. 

 107 }, probably. .V. rnnxcnad. Ravenal. is very poorly described 

 from a single specimen found in a tish at (Miarleston. S. r. It 

 is jirobably this s]>ecies. 



X. VIBKX, Say. PI. 13. ii<r s . 198--207. 



Spire tnrrited. ano-ulatod by a nodulous scries on each whorl, 

 body with a rather broad, sloping' shoulder, the- border of which 



