M0LLUSCA OF THE ' CHALLENGER ' EXPEDITION. 415 



is very much weaker ; but there is a great deal of affinity iu the 

 general features of the shell. 



19. Pleurotoma (Drillia) brachttona, n. sp. {ftpa^vrovos, 

 short.) 



St. 191. September 23, 1874. Lat. 5° 41' S., long. 131° 4' E. 

 Off Am Island, W. of Papua. 800 fms. Mud. Bottom tem- 

 perature 39° - 5. 



Shell. — Short and broad, biconical, angulated, thin, witli small 

 oblique riblets and spiral threads, and with a lop-sided, small- 

 pointed snout. Sculpture. Longitudinals — on the last whorl there 

 are about twenty small, short, oblique riblets which are obsolete 

 on the base ; they are parted by shallow furrows somewhat 

 broader than they : they are more numerous and sharper on the 

 upper whorls, where they occupy the whole lower third of each 

 whorl. Immediately below the suture there is a minute collar of 

 very small, short, sharp, irregular puckers with intervals of twice 

 their own breadth: springing from these puckers and coinciding 

 with the riblets are hair-like lines of growth, which are slightly 

 stronger than the rest, which closely cover the whole surface of 

 the shell. Spirals — there is a slight collar at the top of the whorls, 

 which forms a very minute and irregular shelf on the underside 

 of the suture ; about two thirds down the whorls is a blunt angu- 

 lation where the longitudinal riblets rise. Besides these, there 

 are on the whole surface flatly rounded threads which are broad, 

 . coarse, and irregular on the base, crowded and narrow at the 

 keel, broader, but faint and more regular, on the shoulder. 

 Colour alabaster- white. Spire irregularly conical. Apex eroded. 

 Whorls 8, making allowance for the eroded apex ; they have a 

 long, sloping, slightly concave shoulder, a blunt angulation about 

 two thirds down, and below this are nearly cylindrical : the fifth 

 whorl enlarges somewhat disproportionately ; and the last whorl is 

 swollen, with a sharper angulation than the rest ; the base is con- 

 vexly conical, and is produced into a lop-sided, centrally situated, 

 small-pointed snout. Suture small but distinct, being slightly 

 channelled by the minute horizontal shelf formed by the edge of 

 the infrasutural collar : there is a very slight contraction of the 

 whorls into it. Mouth rather small, rhomboidally pear-shaped, 

 being pointed above, prolonged into the rather short and broad 

 canal below, and having a blunt angulation in the outer lip and 

 at the base of the pillar. Outer lip very thin : it is somewhat 



32* 



