230 



Thais, Liuk, 1807, I. c. iii. p. 114. 



[Thais of Bolteu Mus. includes some Ricinulce and Monoceros of 

 Lamarck, from which Link has depurated it.] 



Spire shorter than the last, veutricose whorl; aperture semicircular; 

 inner lip plane, obliquely cut off, callous, smooth ; outer lip scarcely 

 marginated ; shell without varices ; base short. 



Thais Persica {Bucc), Linn. — patula, Linn. sp. — hcemastoma 

 (Chemn. fig. 964, 965). — -fucus, Gmel. sp. — minuta, Lmk. 



This genus, which is synonymous with Microtoma, Swainson, I 

 should think ad^dsable to be retained at least as a section of the 

 hitherto confused genus Purpura. 



Mancinella, Link, 1807, I. c. iii. p. 115. 



Spire much shorter than the last whorl ; aperture longitudinal, 

 rounded ; inner lip smooth and callous, outer one little or not at all 

 marginated ; shell without varices, but provided with spines and im- 

 bricate scales ; base short, or scarcely elongated, twisted outwards, 

 slightly notched. 



Mancinella aculeata (Chemn. 967, 968). — hystrix, Linn. sp. — 

 castanea. Link (Chemn. 956-958). — armigera, Chemn. sp. — muta- 

 bilis, Chemn. 951-953. — Bezoar, Chemn. 754, 755. 



This genus, combining some Purpurea with some Pyrulce of La- 

 marck, comes near toRapana a, Schum., and perhaps may be adopted. 



VoLEMA, Link, 1807, I. c. iii. p. 115. (Vole)na, Bolt, emend.) 



Spire much shorter than the last whorl, often distorted ; aperture 

 oblong, rounded ; inner lip smooth and callous, outer lip simple ; shell 

 without varices ; if grown old, with spines or imbricated scales ; base 

 elongated, rather turned aside. 



The species are to be found in my ' Ind. Gen. Malacoz.' vol. ii. 

 p. 699. 



This genus unites Busycum, Bolt. {=.Fulgur, Montf.) with Cassi- 

 dulus, Humphr., Gray. 



Xancus, Bolten, 1798, Mus. (edit. 1819, p. 94) ; Link, 1807, I. c. 

 iii. p. 116. 



Spire shorter than the last whorl ; aperture above rounded, wide, 

 below narrow ; inner lip callous, with three folds ; outer lip simple ; 

 shell heavy, without varices or spines ; base elongated. 



Xancus pyrum, Linn . sp ., and maculatus. Link (Chemn . f . 9 1 7, 9 1 8) . 



This genus, by Humphrey called Rapum, by Fabricius Pyrum, by 

 Dr. Gray Turbinellus, and by M. Deshayes Scolymus, is here cha- 

 racterized for the first time, and sufficiently. 



Cymatitjm, Link, 1807, I. c. iii. p. 119. 



Spire rather long ; aperture above rounded ; inner lip callous, with 

 three folds ; outer one marginated ; a great number of crowded and 

 ridged varices run down the shell, to which they are firmly grown ; 

 base little elongated. 



Cymafium polygonnm, &c. 



This is quite identical with Latirus, Montf., or Polyyona, Schum. 



