120 MR. CONKAD'S DESCRIPTIONS 



M. STAMINEA. PI. 12, fig. 4. — Elliptical, whorls eight, slightly turreted, longitudinally ribbed ; ribs small, 

 numerous ; whorls with distinct impressed revolving lines ; body whorl ventricose ; aperture about 

 half the length of the shell ; pillar 4-plaited, the three upper ones nearly equal. Length 4-10. 



M. viCKSBURGENSis. Elliptical, small ; whorls slightly convex, with fine longitudinal ribs, obsolete towards 

 the suture inferiorly and wanting on the lower half of the body ; suture profound ; aperture more 

 than half the length of the shell ; pillar 4-plaited, the three upper ones nearly or quite equal in size. 



Distinguished from the preceding by wanting the revolving lines, and in being 

 wider in proportion to its length. 3-10. 



CARICELLA. 



C. DEMisSA. PI. 12, fig. 5. — Subfusiform; whorls six, convex, one or two whorls near the apex distinctly 

 striated longitudinally, and with minute revolving lines ; upper part of the whorls slightly concave ; 

 apex papillated, first and second volutions smooth, entire ; beak striated ; aperture about two-thirds 

 the length of the shell; columella 4-plaited. Length If. 



SCOBINELLA. 



Shell subfusiform, with a deep angular sinus in the labrum as in Pleurotoma ; spire long, turreted; pillar 

 lip wanting ; columella with plaits decreasing in size downwards, as in Mit7-a ; canal short. 



S, ciELATA. PL 12, fig. 8, 9. — Subfusiform ; volutions eleven, slightly scalariform ; with longitudinal 

 irregular ribs and revolving impressed lines ; ribs interrupted on the spire by a tuberculated convex 

 space; suture margined by a row of fine tubercles or grains; labium with four, rarely five plaits. 

 Length 1 3-10. 



This singular shell is perhaps more nearly related to Pleurotoma than to Mitra. 

 The plaits in most specimens resemble those of the latter genus, but in one instance 

 where there are five plates, the middle is the largest and thickest, the lowest one 

 being minute. 



TURBINELLA. 



T. wiLSONi. Pi. 12, fig. 12. — Fusiform; spire elevated, acute, volutions ten, angular, nodose, the larger 

 volutions somewhat concave above ; the upper volutions with revolving lines, obsolete or wanting on 

 the lower ones ; beak with coarse, slightly raised revolving lines ; aperture narrow ; columella with 

 three rather distant compressed plaits, the middle one largest ; canal long. Length 5 inches. 



The young of this species has distinct lines on every part of the shell, except on 

 the large portion of the body whorl, where they are indistinct and remote. This 

 species is named to commemorate the scientific zeal of Dr. Thomas B. Wilson. It is 

 rare, and generally very imperfect. 



T. PROTRACTA. PI. 12, fig. 7. — Fusiform, with about nine volutions, with thick, prominent, longitudinal 

 ridges, and revolving, thick, prominent lines, with a fine intervening line ; longitudinal wrinkles 

 distinct; whorls concave above; spire elevated, acute ; columella with four plaits, the lower one 

 dentiform; canal long; labrum striated within. Length 1 5-10. 



