438 REV. R. BOOG WATSON ON THE 



a row of small tubercles on the ribs. The surface is covered with 

 very obsolete broadish threads, which are crowded on the body, 

 but on the base are stronger, more regular, and wider apart ; on 

 the snout they are finer and more crowded. The suture is mar- 

 ginated below by a flat thread. Colour almost papyraceous white. 

 Spire is subscalar, narrow, and would be high but for the abrupt- 

 ness with which it is crowned by the apex, consisting of four 

 yellow conically globose whorls, of which the last is large and 

 dome- shaped, and the first minute, prominent, but at the very tip 

 slightly bent down ; the first two are smooth ; the last two are 

 sparsely crossed by minute cusp -like threads or riblets. Whorls 

 7 to 8 in all, rather high, with a drooping shoulder in the 

 sinus-area, which is defined by the angulation below ; below this 

 the upper whorls are nearly cylindrical, while the body-whorl 

 barely convex : this whorl is small ; on the base it is a little con- 

 tracted and drawn out, and is produced into a small and rather 

 lop-sided snout. Suture minute, but impressed and further de- 

 fined by the marginal thread. Mouth small, narrow, pear-shaped, 

 triangular above, and produced below into the relatively broad, 

 open, and deep canal. Older lip flat at the shoulder, feebly angu- 

 lated at the keel, scarcely convex below ; the edge, which is quite 

 independent of the ribs, is very convexly prominent below, with a 

 high and advancing shoulder, above which lies the deep, open- 

 mouthed, rounded sinus. Inner lip is exceedingly narrow ; it is 

 thinly cut into the substance of the shell, and very early runs out 

 on the slightly oblique, narrow, twisted edge of the pillar, which is 

 straight, narrow, and very slightly angulated at its junction with 

 the body. H. 0*25. B. 0-09. Penultimate whorl, height 0*044. 

 Mouth, height 0*13, breadth 0-04 



Probably none of the specimens obtained of this species are 

 quite full-grown. 



38. Plettrotoma (Mangelia) incincta, n. sp. 



St. 78. July 10, 1873. Lat. 37° 26' N., long. 25° 13' W. Off 

 San Miguel, Azores. 1000 fms. Gloligerina-ooze. 



Shell. — High and narrow, with rounded lines, biconical, thin, 

 white, glossy, feebly ribbed, faintly spiralled and slightly keeled, 

 having a high, stout, conical spire ending in a blunt point, with a 

 small long body-whorl, produced base and snout. Sculpture. Lon- 

 gitudinals — there are on each whorl about 22 slight and unequal 

 threads serving as ribs ; they are cusped at the top of the whorls, 



