184 MOLLUSCA. 
Mouth at the end of a short proboscis, armed with a pair of jaws, 
each formed of two subtriangular pieces; lingual ribbon broad, with 
longitudinal ranges of flat spinous processes on each side of the median 
jointed cartilage; the margin fleshy and involute. 
SHELL low conic-globose, rather thin, imperforate, obtusely angular 
at the periphery: whorls five, somewhat flattened, and grooved with 
shallow, unequal, rather broad revolving sulci, quite fine on the base ; 
suture impressed. Aperture obliquely semicircular; lip sharp, green 
at the edge, submargin opaque white; columella acute, with a slight 
gibbosity at the middle; base moderately convex and colourless ; 
general colour olivaceous, usually tessellated above and below by dark 
maroon-coloured, sub-quadrate spots ; fauces pearly, iridescent. 
Diameter seven-eighths of an inch; axis six-eighths of an inch. 
Obtained on the rocks west of Funchal, Madeira Island. [1. p. c.] 
This shell has the form and texture of T. wmbilicaris. It seems not 
to be an uncommon shell, and yet I find no description answering to 
the specimens I have seen. There are three distinct varieties. 
1. The most common has the whorls convex, with faint revolving 
strie of a deep olive-green, with dusky-red maculations. Figure 223. 
2. Whorls convex, shell more conical, quite smooth, uniform green, 
save on the base at the umbilical region, which has a delicate rose- 
tint. Figure 223 a. 
3. Rather depressed, the whorls subcarinate, strongly striate, green, 
tessellated with red; foot of the animal colourless. Figure 223 6. 
TRocHUS TANTILLUS (Gould). 
Testa minuta, conico-discordea, flavido-cinerea, lineis radiantibus flexuo- 
sis fuscis picta: spira depressa, anfractibus quatuor ad quinque 
angulatis, ultimo ad peripheriam dilatato, acuto: basis convexiuscula, 
perforata, flavida, iris duabus concentricis proclivibus munita : aper- 
tura oblaquissima. 
Trochus tantillus, Goud; Proceed. Boston Soc. Nat. Hist., ii. 118. 
May 1849. Expedition Shells, 59. 
