480 
APPENDIX. 
[B. 
Shell depressed, conical, pale reddish, ornamented with rows of 
white and brown spots, spirally g-rooved, ribs slightly granulated ; 
the sutures distinct, impressed, the lower part of the last whorl 
nearly smooth, the umbilicus white, smooth inside, the edge fur- 
nished with a series of granules. The mouth subquadrangular, 
outer lip crenulated at the edge, the columella lip smooth, with a 
large tooth at the inside, and a little roughness on the outer side ; 
axis three-tenths, diameter five-twelfths of an inch. 
31. Monodonta CONSTRICTA, Lam. Hist. vii. 3G. 
32. Monodonta rudis, (n. s.) 
Testa ovato-conica imperforata alhido-purpurea rudis crassa^ 
labro duplicato, extus albido viridi, intus subsulcatOf albo. 
Inhab. Mus, Brit. 
Shell ovate, conical, imperforated, rough, pearly, concentrically 
striated, whitish-brown ; when worn or where eroded, purple ; 
the whorls convex, suture distinct, sometimes occupying an im- 
pressed line on the lower whorl ; the base rather convex, the 
aperture roundish, the axis (imperforate) covered with a white 
callus, which leaves a slight concavity over its end ; the outer lip 
of three colours, the outer part purple or green and white, the 
middle pearly, and the inner opake, white, and furrowed ; the 
surface of the lower part of the last whorl is frequently worn 
away just opposite the mouth, so as to leave a purple spot. 
33. RiSSOA CLATHRATA, (n. S.) 
Testa subglobosa, subimperforata, alba^ solida^ spiraliter 
et concentrice costata ; aperturd suborbiculari, suturd 
impressd. 
Shell nearly globular, spire conical, upper whorls with three, 
lower with seven distinct, large, rather separate, much raised, 
spiral ribs, and numerous acute transverse ribs, which form an 
acute tubercle where it crosses the spiral ridges, the suture deeply 
impressed, very distinct, the aperture nearly orbicular, the outer 
lip denticulated on its outer edge, inner lip smooth, column with- 
out any perforation, only a slight linear cavity behind the inner 
lip, axis and diameter each one-sixth of an inch. 
