bX 
399 
10. AMATHINA BICARINATA, Pease. 
Shell thin, subpellucid, triangularly ovate, contracted posteriorly ; 
colour vitreous-white ; traversed by longitudinal, diverging, irregular- 
sized ribs, two of which are more prominent than the others, giving 
the shell a somewhat bicarmated appearance, and crossed by fine, close, 
concentric lines of growth ; spire consisting of one evolution, recurved 
laterally and projecting beyond the posterior margin of the shell ; 
aperture oval, edges smooth; epidermis thin, membranaceous, covering 
the entire shell. 
11. CoRALLIOBIA CANCELLATA, Pease. 
Shell small, rather solid, depressly ovate, white ; spire concealed by 
the upper termination of the outer lip ; surface coarsely latticed with 
longitudinal and transverse ridges, the former disposed so as to give 
the surface an imbricated appearance; columella smooth, very slightly 
arched, and attenuated below; outer lip widely dilated; aperture large, 
extending the whole length of the shell. 
A singular species, resembling somewhat a minute Concholepas, and 
allied to R. madreporarum (Sow.). Only a single dead specimen 
found. 
12. RuIzoCHILUS EXARATUS, Pease. 
Shell abbreviately ovate, deeply umbilicated; spire short, acute, 
less than one-half the length of the shell; whorls about six, convex, 
subangulated, the last large and gibbous, encircled with small, close, 
irregular, minutely scaled ridges and longitudinal ribs, ribs slightly 
oblique and becoming obsolete or altogether wanting on body-whorl ; 
aperture wide, semicircular, finely and closely lyrate within; outer 
lip thin ; inner lip produced so as to form an even surface with the 
outer lip, smooth and slightly arched ; canal very short and slightly 
recurved ; colour dirty-white. 
13. CoLUMBELLA PELLUCIDA, Pease. 
Shell elongate-oval, turreted, thin, pellucid, smooth, shining ; spire 
prominent, consisting of six or seven volutions ; apex obtuse ; whorls 
smooth, plano-convex, last whorl but slightly swollen, and furnished 
with close obliquely transverse impressed striz on the basal half; su- 
ture impressed, and margined below with a fine spiral impressed line ; 
aperture about one-half the length of the shell, oblong oval, slightly 
effuse above; outer lip simple; columella smooth, slightly arched ; 
whitish horn-colour; last whorl ornamented with one or two rows 
of oblong brown spots and an opake white spot, intermediate rows 
extending to and encircling the lower part of the upper whorls near 
the suture. 
14. CoLUMBELLA LINEATA, Pease. 
Shell small, solid, fusiform, turreted, whitish or variously marked 
with reddish brown; spire acute ; whorls plano-convex, smooth, the 
last somewhat ventricose, and spirally striated at the base; canal 
produced ; sutures faintly impressed ; outer lip thickened by a stout 
7h Rr 
