FAMILY 10. PURPURIFERA. 241 
whorl sometimes forms an umbilicus, and the sutures between the whorls 
are nearly obliterated by the abundant deposition of enamel. Ancilla was 
the word originally used in application to this genus; but as the French 
authors were fearful of confounding their Ancilles with their Ancyles 
(Ancylus), De Roissy substituted the appellation of Anaular, and the 
author of the genus exchanged it for that which is now universally fol- 
lowed. 
The shell of Ancillaria may be described as being highly polished, ob- 
long, somewhat cylindrical, and either notched or emarginated at the 
base, which is ornamented with an oblique varix ; the spire is either short, 
or elongated, the sutures being almost entirely filled up with enamel, and 
the last whorl is inflated, and sometimes, though very rarely, umbili- 
cated ; the aperture is large, and more or less dilated ; the columella is 
swollen, callous, and slightly twisted, and the outer lip is thin, simple 
and acute. The operculum is horny and acuminated. 
Examples. 
Pl. CCLXXII. Fig. 1 and 2. 
ANCILLARIA AUSTRALIS, Sowerby, Species Conchyliorum, Part I. f. 44 
to 46. 
Pl. CCLXXII. Fig. 3. 
Ancittarta Mavritiana, Sowerby, Species Conchyliorum, Part I. f. 1 
and 2. 
Pl. CCLXXII. Fig. 4 and 7. 
ANCILLARIA GLABRATA*, Swainson, Journ. of Science, vol. xvii. p. 285. 
Sowerby, Species Conchyliorum, Part I. f. 60 to 64. 
Eburna glabrata, Lamarck. 
Fig. 4. var. balteata. 
_ Ancillaria balteata, Sowerby, Species Conchyliorum, Part I. f. 56 and 57. 
Eburna balteata, Sowerby, Genera of Shells, No. 19. f. 3 and 4. 
* We have figured a small operculated specimen of this shell from the cabinet of the Rev. 
Mr. Stainforth, for the sake of establishing a fact which has hitherto been disputed; namely, 
that the Ancillariz are provided with an operculum. 
