440 REV. R. BOOG WATSON ON THE 



39. Pleurotoma (Mangelia) tiara, n. sp. 



St. 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. 

 St. Thomas, N. of Culebra Island, Dan. W. Indies. 390 fms. 

 Coral-mud. 



St. 56. May 29, 1873. Lat. 32° 8' 45" N., long. 64° 59' 35 W". 

 Bermudas. 1000 fms. Grrey ooze. Bottom temperature 38°"2. 



Shell. — High and narrow, rather strong, white, spiralled, with 

 a high subscalar spire ending bluntly in a small tip, with a very 

 small body-whorl, a short contracted base, and a very short small 

 snout. Sculpture. Longitudinals — there are a number of hair- 

 like sinuous lines, which in the sinus-area are like bars ; they are 

 parted by flat intervals of about three or four times their width : 

 the lines of growth are very faint. Spirals — there are on each 

 whorl two strong sharp keels which nearly trisect the whorl ; the 

 lower of these is sometimes feeble ; marginating the suture below 

 is a fine thread ; on the base are 8 or 10 sharp and prominent 

 threads of varying and unequal strength ; at the upper end of the 

 snout is another strong thread ; below this is a little furrow, 

 answering, as in Cerithiopsis, to a small nick at the point of the 

 pillar. On the pillar are from two to four more threads of variable 

 strength. Colour porcellaneous white. Spire high, narrow, co- 

 nical, subscalar. Apex a little bluntly conical, consisting of 4 

 to 5 whorls, of whicli the upper ones are small and smooth ; the 

 last two are ornamented with minute ribs or elongated bosses. 

 Whorls about 10 in all, high and narrow, of very slow and regular 

 increase, slightly convex, with a sloping shoulder, rather cylin- 

 drical in the middle, and slightly contracted below ; the last whorl 

 is small, very slightly tumid, with a very contracted base and a 

 small subcylindrical snout, the point of which is slightly reverted 

 and nicked. Suture very minute and concealed, in spite of the 

 contractions of the whorls and the inferior margination. Mouth 

 short, small, and pear-shaped, not narrow, triangularly pointed 

 above, and ending below in the short, rather open canal. Outer lip 

 a pretty regular curve ; its edge is prominent below witli a low 

 shoulder above, leaving a wide funnel-shaped opening for the 

 rather shallow rounded sinus. Inner lip very narrow, thin, and 

 short, dying out early on the narrow twisted oblique edge of the 

 pillar, which is slightly reverted along the side of the canal so as 

 to produce a small twisted furrow. The line of junction of the 

 pillar and the body is very concave. H. 032. B. Oil. Penulti- 

 mate whorl, height 007. Mouth, height 0*12, breadth 006. 



