GASTEROPODA. 177 
ad duodecim insculpta; regione umbilical eburnea: apertura trans- 
versa, sub-rhombea ; columella brevi, acuta, contortd. 
Trochus circumsutus, GoutD; Proceed. Boston Soc. Nat. Hist., iii. 
106. April 1849. Expedition Shells, 57. 
SuELL solid, of medium size, elevated, regularly conical, flat at base, 
acute at apex, composed of nine or ten whorls, which are declivous 
below the suture, with the lower half vertical, and marked with 
slightly oblique, wave-like nodules. The whole surface is sculptured 
by raised, revolving lines, four on the vertical portion of the whorl, 
with a broad one next the suture, and two succeeding small ones. 
The ground colour of the shell is ashy-white, but all the depressed 
portions are dusky-olive, giving the surface the appearance of being 
regularly stitched with olive, the series at the suture being much the 
coarsest. Base cinereous, imperforate, flat; the umbilical region 
polished ; the remainder with about twelve regular, concentric, fine 
grooves. Aperture transverse, oval; columella short, sharp, con- 
torted. 
Diameter nine-tenths of an inch; axis the same. 
Inhabits Madagascar ? 
In form and sculpture this may be compared with the tip of T. pica. 
The peculiar coloration, representing courses of olive-coloured stitches, 
is characteristic. 
Figure 220, profile of the shell; 220a, base of the shell; 2204, 
sculpture of the base, enlarged. 
TRocuus Jucunbus (Gould). 
Testa parva, soda, conica, flammulis radiantibus invicem coccineis 
incarnatis et albis picta: spira anfractibus sex sub-angulatis, filis 
granulosis alternis minoribus cinctis: basis convexiuscula, imper forata, 
liris concentricis linearibus articulatim pictis insculpta ; regione um- 
bilicah indentata: apertura rhombotdea ; columella arcuata, levi ; 
labro simplict. 
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