230 
Tuats, Link, 1807, /. ec. iii. p. 114. 
[Thais of Bolten Mus. includes some Ricinule and Monoceros of 
Lamarck, from which Link has depurated it. } 
Spire shorter than the last, ventricose 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.—hemastoma 
(Chemn. fig. 964, 965).—/fueus, Gmel. sp.—minuta, Link. 
This genus, which is synonymous with Microtoma, Swainson, i 
should think advisable to be retained at least as a section of the 
hitherto confused genus Purpura. 
Mancrinetta, Link, 1807, /. 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).—hystriz, Linn. sp.— 
castanea, Link (Chemn. 956-958).—armigera, Chemn. sp.—muta- 
éilis, Chemn. 951-953.—Bezoar, Chemn. 754, 755. 
This genus, combining some Purpure with some Pyrule of La- 
marck, comes near to Rapana a, Schum., and perhaps may be adopted. 
Vorema, Link, 1807, J. ¢. iii. p. 115. (Volema, 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. 
. 699. 
; This genus unites Busycum, Bolt. (=Fulgur, Montf.) with Cassi- 
dulus, Humphr., Gray. 
Xancus, Bolten, 1798, Mus. (edit. 1819, p. 94) ; Link, 1807, /. e. 
il. 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.917,918). 
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. 
Cymatium, Link, 1807, /. c. ii. 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. 
Cymatium polygonum, &e. 
This is quite identical with Latirvs, Montf., or Polygona, Schum. 
