364; PLEUROTOMID.E. 



proportionally large, on long stalks conjoined with the ten- 

 tacles : foot rounded in front, with small angular corners, 

 pointed behind. 



Shell of an elegant shape, rather solid, opaque, moderately 

 glossy : sculpture, several strong longitudinal ribs, which are 

 usually oblique on the body- whorl and straight on the upper 

 whorls ; the rib near the mouth, which is placed at a little dis- 

 tance from the outer lip, is much longer and broader than the 

 rest ; in some specimens a similar rib or varix may be observed 

 in the middle of the body- whorl ; there are from 14 to 16 ribs 

 on this as well as on the penultimate whorl, 12 on the next, 

 and at the same rate of decrease upwards ; the top whorls are 

 ribless ; the ribs do not extend much below the periphery, nor 

 across the sutural groove ; all the whorls except that at the 

 top (but including the sutural groove) are encircled by flat- 

 tened or thread-like spiral ridges, which are very close-set and 

 mostly alternate in size ; the second whorl from the top (and 

 sometimes also the succeeding whorl) has but a single ridge,, 

 which being in the middle imparts a keeled aspect to that 

 part ; top whorl reticulated ; a slightly nodulous, but not can- 

 cellated, appearance is produced by the intersection of the ribs 

 and ridges ; the whole surface is microscopically and densely 

 granulated lengthwise, especially in the insterstices of the 

 ridges : colour pale fawn, passing into reddish-brown, or indis- 

 tinctly streaked lengthwise with the latter colour ; the peri- 

 phery is marked by a white band, and the part below the 

 suture is sometimes margined by a reddish-brown line which 

 is occasionally interrupted so as to become a row of spots ; the 

 lines which separate the ribs are paler, and the ridges often of 

 a dark hue ; apex yellowish-white : spire elongated : ivhorls 

 10-11, moderately convex, the upper ones somewhat angu- 

 lated ; the last occupies three-fifths of the shell : suture broad 

 and rather deep, formed by the fissural groove : mouth pear- 

 shaped and long ; length nine-twentieths of the shell : canal 

 rather long, broad, and expanded at the opening ; it is some- 

 what twisted or bent backwards, and ends in a deepish and 

 curved notch : outer lip rounded; inside thickened, finely and 

 closely furrowed ; edge rather sharp, notched by the spiral 

 ridges ; it is often deeply coloured within : fissure deep and 

 broad, incurved at the further extremity ; it is defined out- 

 wardly by a sharp angular point ; its previous course is indi- 

 cated by a closed groove similar to that of the last species : 

 inner lip slight and narrow, furnished very near the top of 



